content: <PAGE>   1
  
  
      As filed with the Securities and Exchange Commission on February 4, 2000
  
  ================================================================================
                         SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON, D.C. 20549
                    - - - - - - - - - - - - - - - - - - - - - - -
                                      FORM S-8
                               REGISTRATION STATEMENT
                                        UNDER
                             THE SECURITIES ACT OF 1933
                    - - - - - - - - - - - - - - - - - - - - - - -
          DELAWARE                                         06-1555163
  (STATE OF INCORPORATION)                    (I.R.S. EMPLOYER IDENTIFICATION NO.)
                              MCK COMMUNICATIONS, INC.
                                313 WASHINGTON STREET
                             NEWTON, MASSACHUSETTS 02548
                                   (617) 464-6100
      (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                    OF REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
  
                               FULL TITLE OF THE PLANS
  
                     AMENDED AND RESTATED 1996 STOCK OPTION PLAN
                          1999 STOCK OPTION AND GRANT PLAN
                    - - - - - - - - - - - - - - - - - - - - - - -
                                  STEVEN J. BENSON
                   CHAIRMAN, CHIEF EXECUTIVE OFFICER AND DIRECTOR
                              MCK COMMUNICATIONS, INC.
                                313 WASHINGTON STREET
                             NEWTON, MASSACHUSETTS 02458
                                   (617) 454-6100
  
      (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA
                            CODE, OF AGENT FOR SERVICE)
                    - - - - - - - - - - - - - - - - - - - - - - -
                                   With copies to:
                                     Sally Burke
                              MCK Communications, Inc.
                                313 Washington Street
                             Newton, Massachusetts 02548
                                   (617) 464-6100
  
                           CALCULATION OF REGISTRATION FEE
  <TABLE>
  <CAPTION>
  --------------------- ---------------- -------------------------- ---------------------- ------------------------
  Title of Securities     Amounts to be       Proposed Maximum         Proposed Maximum            Amount of
  Being Registered       Registered (1)   Offering Price Per Share    Aggregate Offering       Registration Fee
                                                                             Price
  
  --------------------- ---------------- -------------------------- ---------------------- ------------------------
  <S>                    <C>                    <C>                     <C>                       <C>
  Common Stock, par
  value $.001 per share     75,345(2)           $ 0.01(2)(3)            $       753.45            $      .20
                           601,242(2)           $ 0.10(2)(3)            $    60,124.20            $    15.87
                           211,151(2)           $ 0.20(2)(3)            $    42,230.20            $    11.15
                           318,240(2)           $ 1.63(2)(3)            $   518,731.20            $   136.95
                           200,813(2)           $ 8.17(2)(3)            $ 1,640,642.20            $   433.13
                           189,655(2)           $12.75(2)(3)            $ 2,418,101.20            $   638.38
                           125,500(2)           $13.50(2)(3)            $ 1,694,250.00            $   447.28
                             2,000              $16.00(3)               $    32,000.00            $     8.45
                               500              $19.50(3)               $     9,750.00            $     2.58
                           129,250              $22.50(3)               $ 2,908,125.00            $   767.75
                             6,500              $23.56(3)               $   153,140.00            $    40.43
                            15,000              $28.63(3)               $   429,450.00            $   113.37
                            10,000              $29.88(3)               $   298,800.00            $    78.88
                         2,361,657              $27.31(4)               $64,496,852.67            $17,027.17
                         ---------                                      --------------            ----------
                         4,246,853                                      $74,702,950.12            $19,721.60
  --------------------- ---------------- -------------------------- ---------------------- ------------------------
  </TABLE>
  
  (1)      Includes 3,060,000 shares to be offered pursuant to the 1999 Stock
           Option and Grant Plan of the Registrant. This Registration Statement
           also relates to such indeterminate number of additional shares of MCK
           Communications, Inc. Common Stock as may be required pursuant to the
           Amended and Restated 1996 Stock Option Plan and the 1999 Stock Option
           and Grant Plan in the event of a stock dividend, reverse stock split,
           split-up, recapitalization, forfeiture of stock under these plans or
           other similar event.
  
  
  <PAGE>   2
  
  
  (2)      The numbers of shares and the price per share of all options issued
           prior to October 8, 1999 reflect a stock split of 1.53 to one that
           occurred on this date.
  
  (3)      The Proposed Maximum Offering Price Per Share and the Proposed
           Aggregate Offering Price are based on the price at which outstanding
           options may be exercised, in accordance with Rule 457(h) under the
           Securities Act of 1933, as amended (the "Securities Act"), and are
           utilized solely for the purpose of calculating the registration fee.
  
  (4)      The Proposed Maximum Offering Price Per Share and the Proposed
           Aggregate Offering Price are based upon the average of the high and low
           prices for the Registrant's Common Stock, par value $.01 per share, as
           reported on the Nasdaq National Market on January 31, 2000, in
           accordance with Rules 457(h) and (c) under the Securities, and are
           utilized solely for the purpose of calculating the registration fee.
  
  
                                       PART I
  
                INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS
  
  Item 1.  PLAN INFORMATION. *
  
  Item 2.  REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION. *
  
           * Information required by Part I to be contained in the Section 10(a)
  Prospectus is omitted from this Registration Statement in accordance with Rule
  428 under the Securities Act of 1933 (the "Securities Act") and the Introductory
  Note to Part I of Form S-8.
  
                                       PART II
  
                 INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  
  Item 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE.
  
           MCK Communications, Inc. (the "Registrant") hereby incorporates by
           reference the following documents which have previously been filed with
           the Securities and Exchange Commission:
  
           (a)      the Registrant's final prospectus dated October 22, 1999 as
                    filed with the Securities and Exchange Commission on October
                    22, 1999 pursuant to Rule 424(b) under the Securities Act (the
                    "Prospectus");
  
           (b)      all other reports filed with the Securities and Exchange
                    Commission by the Registrant pursuant to Section 13(a) or
                    15(d) of the Securities Exchange Act of 1934, as amended (the
                    "Exchange Act") since October 22, 1999; and
  
           (c)      the description of the Registrant's Common Stock contained in
                    the Registration Statement on Form 8-A dated October 18, 1999
                    as filed with the Securities and Exchange Commission on
                    October 18, 1999 pursuant to Section 12(g) of the Securities
                    Exchange Act of 1934, as amended.
  
           In addition, all documents subsequently filed with the Securities and
  Exchange Commission by the Registrant pursuant to Sections 13(a), 13(c), 14 and
  15(d) of the Exchange Act, prior to the filing of a post-effective amendment
  hereto that indicates that all securities offered hereunder have been sold or
  which deregisters all securities then remaining unsold, shall be deemed to be
  incorporated by reference in this Registration Statement and to be a part hereof
  from the date of filing of such
  
  
  
                                         2
  <PAGE>   3
  
  
  documents. Any statement contained in a document incorporated by reference
  herein shall be deemed to be modified or superseded for purposes hereof to the
  extent that a statement contained herein or in any subsequently filed document
  which also is incorporated by reference herein modifies or supersedes such
  statement. Any statement so modified or superseded shall not be deemed, except
  as so modified or superseded, to constitute a part of this Registration
  Statement.
  
  Item 4.  DESCRIPTION OF SECURITIES.
  
           Not Applicable.
  
  Item 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.
  
           Not Applicable.
  
  Item 6   INDEMNIFICATION OF DIRECTORS AND OFFICERS.
  
           In accordance with Section 145 of the General Corporation Law of the
  State of Delaware ("DGCL"), Article VII of the Registrant's Restated Certificate
  of Incorporation (the "Certificate") provides that no director of the Registrant
  shall be personally liable to the Registrant or its stockholders for monetary
  damages for breach of fiduciary duty as a director, except for liability (i) for
  any breach of the director's duty of loyalty to the Registrant or its
  stockholders, (ii) for acts or omissions not in good faith or which involve
  intentional misconduct or a knowing violation of law, (iii) in respect of
  intentional misconduct or a knowing violation of law, (iii) in respect of
  certain unlawful dividend payments or stock redemptions or repurchases, or (iv)
  for any transaction from which the director derived an improper personal
  benefit. In addition, the Certificate provides that if the DGCL is amended to
  authorize the further elimination or limitation of the personal liability of
  directors, then the liability of a director of the Registrant shall be
  eliminated or limited to the fullest extent permitted by the DGCL, as so
  amended.
  
           Article V of the Registrant's Amended and Restated By-laws (the
  "By-laws") provides for indemnification by the Registrant of its directors,
  officers and certain non-officer employees (including officers and certain
  non-officer employees of subsidiaries) under certain circumstances against
  expenses (including attorneys fees, judgments, fines and amounts paid in
  settlement) reasonably incurred in connection with the defense or settlement of
  any threatened, pending or completed legal proceeding in which any such person
  is involved by reason of the fact that such person is or was a director, an
  officer or an employee of the Registrant, or is acting in any capacity with
  other entities at the written request of the registrant, if such person acted in
  good faith and in a manner he or she reasonably believed to be in, or not
  opposed to, the best interests of the Registrant, and with respect to criminal
  actions or proceedings, that such person had no reasonable cause to believe his
  or her conduct was unlawful.
  
           Under Section 7 of the Underwriting Agreement filed as Exhibit 1.1 to
  the MCK Communications, Inc. Registration Statement on Form S-1 (File No.
  33-85281), the Underwriters have agreed to indemnify, under certain conditions,
  the Registrant, its directors, certain officers and persons who control the
  Registrant within the meaning of the Securities Act against certain liabilities.
  
  
  
                                         3
  <PAGE>   4
  
  
           The Company carries directors' and officers' liability insurance
  covering its directors and officers.
  
  Item 7.  EXEMPTION FROM REGISTRATION CLAIMED.
  
           Not applicable.
  
  Item 8.  EXHIBITS.
  
           The following is a complete list of exhibits filed or incorporated by
  reference as part of this Registration Statement.
  
  EXHIBITS
  
           3.3      Form of Second Amended and Restated Certificate of
                    Incorporation of the Registrant*
  
           3.5      Form of First Amended and Restated By-laws of the Registrant*
  
           4.1      Specimen Certificate for Shares of Common Stock, par value
                    $.001 per share, of the Registrant*
  
           5.1      Opinion of McDermott, Will & Emery LLP as to the legality of
                    the securities being offered
  
           10.3     Amended and Restated 1996 Stock Option Plan of the Registrant*
  
           10.4     1999 Stock Option and Grant Plan of the Registrant
  
           23.1     Consent of McDermott, Will & Emery (included in Exhibit 5.1)
  
           23.2     Consent of Ernst & Young LLP
  
           23.3     Consent of PriceWaterhouseCoopers LLP
  
           23.4     Powers of Attorney (included on signature pages to this
                    Registration Statement)
  
  --------------------
  
  *Incorporated by reference to the relevant exhibit to the MCK Communications,
  Inc. Registration Statement on Form S-1 (File No. 333-85821), as amended, as
  filed with the Securities and Exchange Commission.
  
  Item 9.  UNDERTAKINGS.
  
           (a)      The undersigned Registrant hereby undertakes:
  
                    (1) To file, during any period in which offers or sales are
           being made, a post-effective amendment to this Registration Statement:
  
                             (i) to include any prospectus required by Section
                    10(a)(3) of the Securities Act;
  
                             (ii) to reflect in the prospectus any acts or events
                    arising after the effective date of the Registration Statement
                    (or the most recent post-effective amendment thereof) which,
                    individually or in the aggregate, represent a fundamental
                    change in the information set forth in the Registration
                    Statement. Notwithstanding the foregoing, any
  
  
  
                                         4
  <PAGE>   5
  
  
                    increase or decrease in volume of securities offered (if the
                    total dollar value of securities offered would not exceed that
                    which was registered) and any deviation from the low or high
                    end of the estimated offering range may be reflected in the
                    form of prospectus filed with the Commission pursuant to Rule
                    424(b) if, in the aggregate, the changes in volume and price
                    represent no more than a twenty percent (20%) change in the
                    maximum aggregate offering price set forth in the "Calculation
                    of Registration Fee" table in the effective Registration
                    Statement; and
  
                                      (iii) to include any material information
                    with respect to the plan of distribution not previously
                    disclosed in the Registration Statement or any material change
                    to such information in the Registration Statement;
  
           provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) herein do
           not apply if the Registration Statement is on Form S-3, Form S-8 or
           Form F-3, and the information required to be included in a
           post-effective amendment by those paragraphs is contained in periodic
           reports filed by the undersigned Registrant pursuant to Section 13 or
           Section 15 (d) of the Exchange Act that are incorporated by reference
           in the Registration Statement;
  
                    (2) That, for the purpose of determining any liability under
  the Securities Act, each such post-effective amendment shall be deemed to be a
  new registration statement relating to the securities offered therein, and the
  offering of such securities at that time shall be deemed to be the initial bona
  fide offering thereof; and
  
                    (3) To remove from registration by means of a post-effective
  amendment any of the securities being registered which remain unsold at the
  termination of the offering.
  
  (b)      The undersigned Registrant hereby undertakes that, for purposes of
           determining any liability under the Securities Act, each filing of the
           registrant's annual report pursuant to Section 13(a) or 15(d) of the
           Exchange Act (and, where applicable, each filing of an employee benefit
           plan's annual report pursuant to Section 15(d) of the Exchange Act)
           that is incorporated by reference in the Registration Statement shall
           be deemed to be a new registration statement relating to the securities
           offered therein, and the offering of such securities at that time shall
           be deemed to be the initial bona fide offering thereof.
  
  (c)      Insofar as indemnification for liabilities arising under the Securities
           Act may be permitted to directors, officers and controlling persons of
           the Registrant pursuant to the foregoing provisions, or otherwise, the
           Registrant has been advised that in the opinion of the Securities and
           Exchange Commission such indemnification is against public policy as
           expressed in the Securities Act, and is, therefore, unenforceable. In
           the event that a claim for indemnification against such liabilities
           (other than the payment by the registrant of expenses incurred or paid
           by a director, officer or controlling person of the registrant in the
           successful defense of any action, suit or proceeding) is asserted by
           such director, officer or controlling person in connection with the
           securities being registered, the registrant will, unless in the opinion
           of its counsel the matter has been settled by controlling precedent,
           submit to a court of appropriate jurisdiction the question whether such
           indemnification by it is against public policy as expressed in the
           Securities Act and will be governed by the final adjudication of such
           issue.
  
  
  
  
                                         5
  <PAGE>   6
  
  
           Pursuant to the requirements of the Securities Act, MCK Communications,
  Inc. certifies that it has reasonable grounds to believe that it meets all of
  the requirements for filing on Form S-8 and has duly caused this Registration
  Statement to be signed on its behalf by the undersigned, thereunto duly
  authorized in Newton, Massachusetts on January 31, 2000.
  
                              MCK Communications, Inc.
  
                              By: /s/ Steven J. Benson
                                  --------------------
                                  Steven J. Benson
                                  Chairman, Chief Executive Officer and President
  
                                  POWER OF ATTORNEY
  
           KNOW ALL MEN BY THESE PRESENTS that each individual whose signature
  appears below constitutes and appoints each of Steven J. Benson and Paul K.
  Zurlo such person's true and lawful attorney-in-fact and agent with full power
  of substitution and resubstitution for such period and in such person's name,
  place and stead, in any and all capacities, to sign any and all amendments
  (including post-effective amendments) to this Registration Statement, and to
  file with same, with all exhibits thereto, and all documents in connection
  therewith, with the Securities and Exchange Commission, granting unto each said
  attorney-in-fact and agent full power and authority to do and perform each and
  every act and thing requisite and necessary to be done in and about the
  premises, as fully to all intents and purposes as such person might or could do
  in person, hereby ratifying and confirming all that any said attorney-in-fact
  and agent, or any substitute or substitutes of any of them, may lawfully do or
  cause to be done by virtue hereof.
  
           Pursuant to the requirements of the Securities Act of 1933, this
  Registration Statement has been signed by the following persons in the
  capacities and on the dates indicated.
  
  SIGNATURE                    TITLE                                    DATE
  
  /s/ Steven J. Benson         Chairman of the Board, (Chief      January 31, 2000
  ------------------------     Executive Officer, President,
  Steven J. Benson             Chairman and Director)
  
  /s/ Paul K. Zurlo            Chief Financial Officer            January 31, 2000
  ------------------------     (Principal Financial
  Paul K. Zurlo                and Accounting Officer)
  
  /s/ Calvin K. Manz           Director                           January 31, 2000
  ------------------------
  Calvin K. Manz
  
  /s/ John B. Landry           Director                           January 31, 2000
  ------------------------
  John B. Landry
  
  /s/ Gregory M. Avis          Director                           January 31, 2000
  ------------------------
  Gregory M. Avis
  
  /s/ Michael H. Balmuth       Director                           January 31, 2000
  ------------------------
  Michael H. Balmuth
  
  /s/ Paul Severino            Director                           January 31, 2000
  ------------------------
  Paul Severino
  
  
  
                                         6
  <PAGE>   7
  
  
  
                                    EXHIBIT INDEX
  
  
  EXHIBITS
  
           3.3      Form of Second Amended and Restated Certificate of
                    Incorporation of the Registrant*
  
           3.5      Form of First Amended and Restated By-laws of the Registrant*
  
           4.1      Specimen Certificate for Shares of Common Stock, par value
                    $.001 per share, of the Registrant*
  
           5.1      Opinion of McDermott, Will & Emery LLP as to the legality of
                    the securities being offered
  
           10.3     Amended and Restated 1996 Stock Option Plan of the Registrant*
  
           10.4     1999 Stock Option and Grant Plan of the Registrant
  
           23.1     Consent of McDermott, Will & Emery (included in Exhibit 5.1)
  
           23.2     Consent of Ernst & Young LLP
  
           23.3     Consent of PriceWaterhouseCoopers LLP
  
           23.4     Powers of Attorney (included on signature pages to this
                    Registration Statement)
  
  --------------------
  
  *Incorporated by reference to the relevant exhibit to the MCK Communications,
  Inc. Registration Statement on Form S-1 (File No. 333-85821), as amended, as
  filed with the Securities and Exchange Commission.
  
  
  
  
  
                                         7
metadata_documents: [{"type": "S-8", "sequence": "1", "description": "MCK COMMUNICATIONS FORM S-8", "secsgml_size_bytes": 22786}]
metadata_filer: {"company-data": {"conformed-name": "MCK COMMUNICATIONS INC", "cik": "0001093576", "assigned-sic": "3661", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-96235", "film-number": "524671"}, "business-address": {"street1": "313 WASHINGTON ST", "city": "NEWTON", "state": "MA", "zip": "02458", "phone": "6174546100"}, "mail-address": {"street1": "313 WASHINGTON ST", "city": "NEWTON", "state": "MA", "zip": "02458"}}
text: 1
  
      As filed with the Securities and Exchange Commission on February 4, 2000
  
  ================================================================================
                         SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON, D.C. 20549
                    - - - - - - - - - - - - - - - - - - - - - - -
                                      FORM S-8
                               REGISTRATION STATEMENT
                                        UNDER
                             THE SECURITIES ACT OF 1933
                    - - - - - - - - - - - - - - - - - - - - - - -
          DELAWARE                                         06-1555163
  (STATE OF INCORPORATION)                    (I.R.S. EMPLOYER IDENTIFICATION NO.)
                              MCK COMMUNICATIONS, INC.
                                313 WASHINGTON STREET
                             NEWTON, MASSACHUSETTS 02548
                                   (617) 464-6100
      (ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA CODE,
                    OF REGISTRANT'S PRINCIPAL EXECUTIVE OFFICES)
  
                               FULL TITLE OF THE PLANS
  
                     AMENDED AND RESTATED 1996 STOCK OPTION PLAN
                          1999 STOCK OPTION AND GRANT PLAN
                    - - - - - - - - - - - - - - - - - - - - - - -
                                  STEVEN J. BENSON
                   CHAIRMAN, CHIEF EXECUTIVE OFFICER AND DIRECTOR
                              MCK COMMUNICATIONS, INC.
                                313 WASHINGTON STREET
                             NEWTON, MASSACHUSETTS 02458
                                   (617) 454-6100
  
      (NAME, ADDRESS, INCLUDING ZIP CODE, AND TELEPHONE NUMBER, INCLUDING AREA
                            CODE, OF AGENT FOR SERVICE)
                    - - - - - - - - - - - - - - - - - - - - - - -
                                   With copies to:
                                     Sally Burke
                              MCK Communications, Inc.
                                313 Washington Street
                             Newton, Massachusetts 02548
                                   (617) 464-6100
  
                           CALCULATION OF REGISTRATION FEE
  --------------------- ---------------- -------------------------- ---------------------- ------------------------
  Title of Securities     Amounts to be       Proposed Maximum         Proposed Maximum            Amount of
  Being Registered       Registered (1)   Offering Price Per Share    Aggregate Offering       Registration Fee
                                                                             Price
  
  --------------------- ---------------- -------------------------- ---------------------- ------------------------
  Common Stock, par
  value $.001 per share     75,345(2)           $ 0.01(2)(3)            $       753.45            $      .20
                           601,242(2)           $ 0.10(2)(3)            $    60,124.20            $    15.87
                           211,151(2)           $ 0.20(2)(3)            $    42,230.20            $    11.15
                           318,240(2)           $ 1.63(2)(3)            $   518,731.20            $   136.95
                           200,813(2)           $ 8.17(2)(3)            $ 1,640,642.20            $   433.13
                           189,655(2)           $12.75(2)(3)            $ 2,418,101.20            $   638.38
                           125,500(2)           $13.50(2)(3)            $ 1,694,250.00            $   447.28
                             2,000              $16.00(3)               $    32,000.00            $     8.45
                               500              $19.50(3)               $     9,750.00            $     2.58
                           129,250              $22.50(3)               $ 2,908,125.00            $   767.75
                             6,500              $23.56(3)               $   153,140.00            $    40.43
                            15,000              $28.63(3)               $   429,450.00            $   113.37
                            10,000              $29.88(3)               $   298,800.00            $    78.88
                         2,361,657              $27.31(4)               $64,496,852.67            $17,027.17
                         ---------                                      --------------            ----------
                         4,246,853                                      $74,702,950.12            $19,721.60
  --------------------- ---------------- -------------------------- ---------------------- ------------------------
  (1)      Includes 3,060,000 shares to be offered pursuant to the 1999 Stock
           Option and Grant Plan of the Registrant. This Registration Statement
           also relates to such indeterminate number of additional shares of MCK
           Communications, Inc. Common Stock as may be required pursuant to the
           Amended and Restated 1996 Stock Option Plan and the 1999 Stock Option
           and Grant Plan in the event of a stock dividend, reverse stock split,
           split-up, recapitalization, forfeiture of stock under these plans or
           other similar event.
  2
  
  (2)      The numbers of shares and the price per share of all options issued
           prior to October 8, 1999 reflect a stock split of 1.53 to one that
           occurred on this date.
  
  (3)      The Proposed Maximum Offering Price Per Share and the Proposed
           Aggregate Offering Price are based on the price at which outstanding
           options may be exercised, in accordance with Rule 457(h) under the
           Securities Act of 1933, as amended (the "Securities Act"), and are
           utilized solely for the purpose of calculating the registration fee.
  
  (4)      The Proposed Maximum Offering Price Per Share and the Proposed
           Aggregate Offering Price are based upon the average of the high and low
           prices for the Registrant's Common Stock, par value $.01 per share, as
           reported on the Nasdaq National Market on January 31, 2000, in
           accordance with Rules 457(h) and (c) under the Securities, and are
           utilized solely for the purpose of calculating the registration fee.
  
                                       PART I
  
                INFORMATION REQUIRED IN THE SECTION 10(A) PROSPECTUS
  
  Item 1.  PLAN INFORMATION. *
  
  Item 2.  REGISTRANT INFORMATION AND EMPLOYEE PLAN ANNUAL INFORMATION. *
  
           * Information required by Part I to be contained in the Section 10(a)
  Prospectus is omitted from this Registration Statement in accordance with Rule
  428 under the Securities Act of 1933 (the "Securities Act") and the Introductory
  Note to Part I of Form S-8.
  
                                       PART II
  
                 INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  
  Item 3.  INCORPORATION OF CERTAIN DOCUMENTS BY REFERENCE.
  
           MCK Communications, Inc. (the "Registrant") hereby incorporates by
           reference the following documents which have previously been filed with
           the Securities and Exchange Commission:
  
           (a)      the Registrant's final prospectus dated October 22, 1999 as
                    filed with the Securities and Exchange Commission on October
                    22, 1999 pursuant to Rule 424(b) under the Securities Act (the
                    "Prospectus");
  
           (b)      all other reports filed with the Securities and Exchange
                    Commission by the Registrant pursuant to Section 13(a) or
                    15(d) of the Securities Exchange Act of 1934, as amended (the
                    "Exchange Act") since October 22, 1999; and
  
           (c)      the description of the Registrant's Common Stock contained in
                    the Registration Statement on Form 8-A dated October 18, 1999
                    as filed with the Securities and Exchange Commission on
                    October 18, 1999 pursuant to Section 12(g) of the Securities
                    Exchange Act of 1934, as amended.
  
           In addition, all documents subsequently filed with the Securities and
  Exchange Commission by the Registrant pursuant to Sections 13(a), 13(c), 14 and
  15(d) of the Exchange Act, prior to the filing of a post-effective amendment
  hereto that indicates that all securities offered hereunder have been sold or
  which deregisters all securities then remaining unsold, shall be deemed to be
  incorporated by reference in this Registration Statement and to be a part hereof
  from the date of filing of such
  
                                         2
  3
  
  documents. Any statement contained in a document incorporated by reference
  herein shall be deemed to be modified or superseded for purposes hereof to the
  extent that a statement contained herein or in any subsequently filed document
  which also is incorporated by reference herein modifies or supersedes such
  statement. Any statement so modified or superseded shall not be deemed, except
  as so modified or superseded, to constitute a part of this Registration
  Statement.
  
  Item 4.  DESCRIPTION OF SECURITIES.
  
           Not Applicable.
  
  Item 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.
  
           Not Applicable.
  
  Item 6   INDEMNIFICATION OF DIRECTORS AND OFFICERS.
  
           In accordance with Section 145 of the General Corporation Law of the
  State of Delaware ("DGCL"), Article VII of the Registrant's Restated Certificate
  of Incorporation (the "Certificate") provides that no director of the Registrant
  shall be personally liable to the Registrant or its stockholders for monetary
  damages for breach of fiduciary duty as a director, except for liability (i) for
  any breach of the director's duty of loyalty to the Registrant or its
  stockholders, (ii) for acts or omissions not in good faith or which involve
  intentional misconduct or a knowing violation of law, (iii) in respect of
  intentional misconduct or a knowing violation of law, (iii) in respect of
  certain unlawful dividend payments or stock redemptions or repurchases, or (iv)
  for any transaction from which the director derived an improper personal
  benefit. In addition, the Certificate provides that if the DGCL is amended to
  authorize the further elimination or limitation of the personal liability of
  directors, then the liability of a director of the Registrant shall be
  eliminated or limited to the fullest extent permitted by the DGCL, as so
  amended.
  
           Article V of the Registrant's Amended and Restated By-laws (the
  "By-laws") provides for indemnification by the Registrant of its directors,
  officers and certain non-officer employees (including officers and certain
  non-officer employees of subsidiaries) under certain circumstances against
  expenses (including attorneys fees, judgments, fines and amounts paid in
  settlement) reasonably incurred in connection with the defense or settlement of
  any threatened, pending or completed legal proceeding in which any such person
  is involved by reason of the fact that such person is or was a director, an
  officer or an employee of the Registrant, or is acting in any capacity with
  other entities at the written request of the registrant, if such person acted in
  good faith and in a manner he or she reasonably believed to be in, or not
  opposed to, the best interests of the Registrant, and with respect to criminal
  actions or proceedings, that such person had no reasonable cause to believe his
  or her conduct was unlawful.
  
           Under Section 7 of the Underwriting Agreement filed as Exhibit 1.1 to
  the MCK Communications, Inc. Registration Statement on Form S-1 (File No.
  33-85281), the Underwriters have agreed to indemnify, under certain conditions,
  the Registrant, its directors, certain officers and persons who control the
  Registrant within the meaning of the Securities Act against certain liabilities.
  
                                         3
  4
  
           The Company carries directors' and officers' liability insurance
  covering its directors and officers.
  
  Item 7.  EXEMPTION FROM REGISTRATION CLAIMED.
  
           Not applicable.
  
  Item 8.  EXHIBITS.
  
           The following is a complete list of exhibits filed or incorporated by
  reference as part of this Registration Statement.
  
  EXHIBITS
  
           3.3      Form of Second Amended and Restated Certificate of
                    Incorporation of the Registrant*
  
           3.5      Form of First Amended and Restated By-laws of the Registrant*
  
           4.1      Specimen Certificate for Shares of Common Stock, par value
                    $.001 per share, of the Registrant*
  
           5.1      Opinion of McDermott, Will & Emery LLP as to the legality of
                    the securities being offered
  
           10.3     Amended and Restated 1996 Stock Option Plan of the Registrant*
  
           10.4     1999 Stock Option and Grant Plan of the Registrant
  
           23.1     Consent of McDermott, Will & Emery (included in Exhibit 5.1)
  
           23.2     Consent of Ernst & Young LLP
  
           23.3     Consent of PriceWaterhouseCoopers LLP
  
           23.4     Powers of Attorney (included on signature pages to this
                    Registration Statement)
  
  --------------------
  
  *Incorporated by reference to the relevant exhibit to the MCK Communications,
  Inc. Registration Statement on Form S-1 (File No. 333-85821), as amended, as
  filed with the Securities and Exchange Commission.
  
  Item 9.  UNDERTAKINGS.
  
           (a)      The undersigned Registrant hereby undertakes:
  
                    (1) To file, during any period in which offers or sales are
           being made, a post-effective amendment to this Registration Statement:
  
                             (i) to include any prospectus required by Section
                    10(a)(3) of the Securities Act;
  
                             (ii) to reflect in the prospectus any acts or events
                    arising after the effective date of the Registration Statement
                    (or the most recent post-effective amendment thereof) which,
                    individually or in the aggregate, represent a fundamental
                    change in the information set forth in the Registration
                    Statement. Notwithstanding the foregoing, any
  
                                         4
  5
  
                    increase or decrease in volume of securities offered (if the
                    total dollar value of securities offered would not exceed that
                    which was registered) and any deviation from the low or high
                    end of the estimated offering range may be reflected in the
                    form of prospectus filed with the Commission pursuant to Rule
                    424(b) if, in the aggregate, the changes in volume and price
                    represent no more than a twenty percent (20%) change in the
                    maximum aggregate offering price set forth in the "Calculation
                    of Registration Fee" table in the effective Registration
                    Statement; and
  
                                      (iii) to include any material information
                    with respect to the plan of distribution not previously
                    disclosed in the Registration Statement or any material change
                    to such information in the Registration Statement;
  
           provided, however, that paragraphs (a)(1)(i) and (a)(1)(ii) herein do
           not apply if the Registration Statement is on Form S-3, Form S-8 or
           Form F-3, and the information required to be included in a
           post-effective amendment by those paragraphs is contained in periodic
           reports filed by the undersigned Registrant pursuant to Section 13 or
           Section 15 (d) of the Exchange Act that are incorporated by reference
           in the Registration Statement;
  
                    (2) That, for the purpose of determining any liability under
  the Securities Act, each such post-effective amendment shall be deemed to be a
  new registration statement relating to the securities offered therein, and the
  offering of such securities at that time shall be deemed to be the initial bona
  fide offering thereof; and
  
                    (3) To remove from registration by means of a post-effective
  amendment any of the securities being registered which remain unsold at the
  termination of the offering.
  
  (b)      The undersigned Registrant hereby undertakes that, for purposes of
           determining any liability under the Securities Act, each filing of the
           registrant's annual report pursuant to Section 13(a) or 15(d) of the
           Exchange Act (and, where applicable, each filing of an employee benefit
           plan's annual report pursuant to Section 15(d) of the Exchange Act)
           that is incorporated by reference in the Registration Statement shall
           be deemed to be a new registration statement relating to the securities
           offered therein, and the offering of such securities at that time shall
           be deemed to be the initial bona fide offering thereof.
  
  (c)      Insofar as indemnification for liabilities arising under the Securities
           Act may be permitted to directors, officers and controlling persons of
           the Registrant pursuant to the foregoing provisions, or otherwise, the
           Registrant has been advised that in the opinion of the Securities and
           Exchange Commission such indemnification is against public policy as
           expressed in the Securities Act, and is, therefore, unenforceable. In
           the event that a claim for indemnification against such liabilities
           (other than the payment by the registrant of expenses incurred or paid
           by a director, officer or controlling person of the registrant in the
           successful defense of any action, suit or proceeding) is asserted by
           such director, officer or controlling person in connection with the
           securities being registered, the registrant will, unless in the opinion
           of its counsel the matter has been settled by controlling precedent,
           submit to a court of appropriate jurisdiction the question whether such
           indemnification by it is against public policy as expressed in the
           Securities Act and will be governed by the final adjudication of such
           issue.
  
                                         5
  6
  
           Pursuant to the requirements of the Securities Act, MCK Communications,
  Inc. certifies that it has reasonable grounds to believe that it meets all of
  the requirements for filing on Form S-8 and has duly caused this Registration
  Statement to be signed on its behalf by the undersigned, thereunto duly
  authorized in Newton, Massachusetts on January 31, 2000.
  
                              MCK Communications, Inc.
  
                              By: /s/ Steven J. Benson
                                  --------------------
                                  Steven J. Benson
                                  Chairman, Chief Executive Officer and President
  
                                  POWER OF ATTORNEY
  
           KNOW ALL MEN BY THESE PRESENTS that each individual whose signature
  appears below constitutes and appoints each of Steven J. Benson and Paul K.
  Zurlo such person's true and lawful attorney-in-fact and agent with full power
  of substitution and resubstitution for such period and in such person's name,
  place and stead, in any and all capacities, to sign any and all amendments
  (including post-effective amendments) to this Registration Statement, and to
  file with same, with all exhibits thereto, and all documents in connection
  therewith, with the Securities and Exchange Commission, granting unto each said
  attorney-in-fact and agent full power and authority to do and perform each and
  every act and thing requisite and necessary to be done in and about the
  premises, as fully to all intents and purposes as such person might or could do
  in person, hereby ratifying and confirming all that any said attorney-in-fact
  and agent, or any substitute or substitutes of any of them, may lawfully do or
  cause to be done by virtue hereof.
  
           Pursuant to the requirements of the Securities Act of 1933, this
  Registration Statement has been signed by the following persons in the
  capacities and on the dates indicated.
  
  SIGNATURE                    TITLE                                    DATE
  
  /s/ Steven J. Benson         Chairman of the Board, (Chief      January 31, 2000
  ------------------------     Executive Officer, President,
  Steven J. Benson             Chairman and Director)
  
  /s/ Paul K. Zurlo            Chief Financial Officer            January 31, 2000
  ------------------------     (Principal Financial
  Paul K. Zurlo                and Accounting Officer)
  
  /s/ Calvin K. Manz           Director                           January 31, 2000
  ------------------------
  Calvin K. Manz
  
  /s/ John B. Landry           Director                           January 31, 2000
  ------------------------
  John B. Landry
  
  /s/ Gregory M. Avis          Director                           January 31, 2000
  ------------------------
  Gregory M. Avis
  
  /s/ Michael H. Balmuth       Director                           January 31, 2000
  ------------------------
  Michael H. Balmuth
  
  /s/ Paul Severino            Director                           January 31, 2000
  ------------------------
  Paul Severino
  
                                         6
  7
  
                                    EXHIBIT INDEX
  
  EXHIBITS
  
           3.3      Form of Second Amended and Restated Certificate of
                    Incorporation of the Registrant*
  
           3.5      Form of First Amended and Restated By-laws of the Registrant*
  
           4.1      Specimen Certificate for Shares of Common Stock, par value
                    $.001 per share, of the Registrant*
  
           5.1      Opinion of McDermott, Will & Emery LLP as to the legality of
                    the securities being offered
  
           10.3     Amended and Restated 1996 Stock Option Plan of the Registrant*
  
           10.4     1999 Stock Option and Grant Plan of the Registrant
  
           23.1     Consent of McDermott, Will & Emery (included in Exhibit 5.1)
  
           23.2     Consent of Ernst & Young LLP
  
           23.3     Consent of PriceWaterhouseCoopers LLP
  
           23.4     Powers of Attorney (included on signature pages to this
                    Registration Statement)
  
  --------------------
  
  *Incorporated by reference to the relevant exhibit to the MCK Communications,
  Inc. Registration Statement on Form S-1 (File No. 333-85821), as amended, as
  filed with the Securities and Exchange Commission.
  
                                         7