content: <PAGE>   1
       As filed with the Securities and Exchange Commission on April 21, 1997
  
                                                             Registration No. 333-
  
  ================================================================================
  
                         SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON, D.C. 20549
  
                            -------------------------
  
                                      FORM S-8
  
              REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933
  
                            -------------------------
  
                                ILEX ONCOLOGY, INC.
               (Exact name of registrant as specified in its charter)
  
  
                  DELAWARE                                   74-2699185
       (State or other jurisdiction of        (I.R.S. Employer Identification No.)
       incorporation or organization)             
                                               
                                               
           11550 IH 10 WEST, SUITE 300           
               SAN ANTONIO, TEXAS                              78230
     (Address of Principal Executive Offices)                (Zip Code)
                                       
       
  
  
                     ILEX ONCOLOGY, INC. 1995 STOCK OPTION PLAN
  
                   ILEX ONCOLOGY, INC. 1996 NON-EMPLOYEE DIRECTOR
                                 STOCK OPTION PLAN
                             (Full title of the plans)
  
                                  RICHARD L. LOVE
                                   PRESIDENT AND
                              CHIEF EXECUTIVE OFFICER
                                ILEX ONCOLOGY, INC.
                            11550 IH 10 WEST, SUITE 300
                             SAN ANTONIO, TEXAS  78230
                      (Name and address of agent for service)
  
                                   (210) 949-8200
           (Telephone number, including area code, of agent for service)
  
                            -------------------------
  
                                   With Copy to:
  
                            Fulbright & Jaworski L.L.P.
                           300 Convent Street, Suite 2200
                              San Antonio, Texas 78205
                                   (210) 224-5575
                            Attention: Phillip M. Renfro
  
                            -------------------------
  
                          CALCULATION OF REGISTRATION FEE
  
  
  <TABLE>
  <CAPTION>
  ==========================================================================================================================
                                                                                              Proposed       
                                                                      Proposed Maximum        Maximum            Amount of
         Title of Securities to be                                   Offering Price Per      Aggregate         Registration
                Registered                Amount to be registered        Share (1)         Offering Price (1)      Fee
  --------------------------------------------------------------------------------------------------------------------------
   <S>            <C>                         <C>                          <C>              <C>                 <C>
   Common Stock,  $.01 par value . . .        1,313,078 shares             $12.32           $16,177,121         $4,903
  --------------------------------------------------------------------------------------------------------------------------
   Total . . . . . . . . . . . . . . .                                                      $16,177,121         $4,903
  ==========================================================================================================================
  </TABLE>
  
  (1)      Estimated in accordance with Rule 457(c) and (h) solely for the
           purpose of calculating the registration fee on the basis of the
           average of the high and low prices of the Common Stock as reported by
           the National Market System of NASDAQ on April 16, 1997.
  
  ================================================================================
  <PAGE>   2
                                      PART II
  
                 INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  
  
  ITEM 3.        INCORPORATION OF DOCUMENTS BY REFERENCE.
  
                 The following documents are hereby incorporated by reference in
  this Registration Statement:
  
                 1.       The prospectus of ILEX Oncology, Inc., a Delaware
  corporation (the "Registrant" or the "Company"), filed with Registration
  Statement No. 333-17769 pursuant to Rule 424(b) under the Securities of 1933,
  as amended (the "Securities Act"), which contains audited financial statements
  of the Registrant for the fiscal year ended December 31, 1996;
  
                 2.       All other reports filed pursuant to Section 13(a) or
  15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"),
  since the effective date of the Registration Statement No. 333-17769; and
  
                 3.       The description of the Registrant's common stock, $.01
  par value (the "Common Stock"), set forth under the caption "Description of the
  Registrant's Securities to be Registered" contained in the Registrant's Form
  8-A, filed by the Registrant with the Securities Exchange Commission pursuant
  to the Exchange Act on February 11, 1997.
  
                 All documents filed by the Registrant pursuant to Sections
  13(a), 13(c), 14 and 15(d) of the Exchange Act subsequent to the date of the
  filing hereof and prior to the filing of a post-effective amendment which
  indicates that all securities offered 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 documents.
  
  
  ITEM 4.        DESCRIPTION OF SECURITIES.
  
                 Not applicable.
  
  
  ITEM 5.        INTERESTS OF NAMED EXPERTS AND COUNSEL.
  
                 Not applicable.
  
  
  ITEM 6.        INDEMNIFICATION OF DIRECTORS AND OFFICERS.
  
                 Section 145 of the Delaware General Corporation Law empowers the
  Registrant to, and the Bylaws of the Registrant provide that it shall,
  indemnify any person who was or is a party or is threatened to be made a party
  to any threatened, pending or completed action, suit or proceeding by reason of
  the fact that he is or was a director, officer, employee or agent of the
  Registrant, or is or was serving at the
  
  
  
  
  
                                        II-1
  <PAGE>   3
  request of the Registrant as a director, officer, employee or agent of another
  corporation, partnership, joint venture, trust or other enterprise, against
  expenses, judgments, fines and amounts paid in settlement actually and
  reasonably incurred by him in connection with such action, suit or proceeding
  if he acted in good faith and in a manner he reasonably believed to be in or
  not opposed to the best interest of the Registrant, and, with respect to any
  criminal action or proceeding, had no reasonable cause to believe his conduct
  was unlawful; except that, in the case of an action or suit by or in the right
  of the Registrant, no indemnification may be made in respect of any claim,
  issue or matter as to which such person shall have been adjudged to be liable
  for negligence or misconduct in the performance of his duty to the Registrant
  unless and only to the extent that the Court of Chancery or the court in which
  such action or suit was brought shall determine that such person is fairly and
  reasonably entitled to indemnity for proper expenses.
  
  
  ITEM 7.        EXEMPTION FROM REGISTRATION CLAIMED.
  
                 Not applicable.
  
  
  ITEM 8.        EXHIBITS.
  
       3.1    Amended and Restated Certificate of Incorporation of the Company
              (incorporated by reference to Exhibit 3.1 of the Company's
              Registration Statement on Form S-1, as amended (Reg. No.
              333-17769)).
  
       3.2    Bylaws of the Company, as amended (incorporated by reference to
              Exhibit 3.2 of the Company's Registration Statement on Form S-1, as
              amended (Reg. No. 333-17769)).
  
       4.1    Specimen Common Stock Certificate (incorporated by reference to
              Exhibit 4.1 of the Company's Registration Statement on Form S-1, as
              amended (Reg. No. 333-17769)).
  
       4.2    ILEX Oncology, Inc. 1995 Stock Option Plan (incorporated by
              reference to Exhibit 10.47 of the Company's Registration Statement
              on Form S-1, as amended (Reg. No. 333-17769)).
  
  *    4.3    Form of Incentive Stock Option Agreement under the 1995 Stock
              Option Plan.
  
       4.4    ILEX Oncology, Inc. 1996 Non-Employee Director Stock Option Plan
              (incorporated by reference to Exhibit 10.48 of the Company's
              Registration Statement on Form S-1, as amended (Reg. No.
              333-17769)).
  
       4.5    Form of Non-Employee Director Stock Option Agreement under the 1996
              Non-Employee Director Stock Option Plan (incorporated by reference
              to Exhibit 10.49 of the Company's Registration Statement on Form
              S-1, as amended (Reg. No. 333-17769)).
  
  *    5.1    Opinion of Fulbright & Jaworski L.L.P.
  
  
  
  
  
                                        II-2
  <PAGE>   4
  *   23.1    Consent of Arthur Andersen LLP.
  
  *   23.3    Consent of Fulbright & Jaworski L.L.P. (included in  Exhibit 5.1).
  
  *   24.1    Powers of Attorney from certain members of the Board of Directors
              of the Company (included at II-5).  
  
  --------------------
  
  *           Filed herewith.
  
  ITEM 9.     UNDERTAKINGS.
  
                 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 facts or
                          events arising after the effective date of this
                          Registration Statement (or the most recent
                          post-effective amendment hereof) which, individually or
                          in the aggregate, represent a fundamental change in the
                          information set forth in this Registration Statement;
                          and
  
                          (iii)   To include any material information with
                          respect to the plan of distribution not previously
                          disclosed in this Registration Statement or any
                          material change to such information in this
                          Registration Statement;
  
                 provided, however, that paragraphs (i) and (ii) do not apply if
                 the information required to be included in a post-effective
                 amendment by those paragraphs is contained in periodic reports
                 filed by the Registrant pursuant to Section 13 or Section 15(d)
                 of the Exchange Act of 1934 that are incorporated by reference
                 in this 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 herein, and the offering of such
                 securities at that time shall be deemed to be the initial bona
                 fide offering thereof.
  
                 (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.
  
                 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 Section 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 this
  
  
  
  
  
                                        II-3
  <PAGE>   5
  Registration Statement shall be deemed to be a new registration statement
  relating to the securities offered herein, and the offering of such securities
  at that time shall be deemed to be the initial bona fide offering thereof.
  
                 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.
  
  
  
  
  
                                        II-4
  <PAGE>   6
                                     SIGNATURES
  
          PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT, AS AMENDED, THE
  REGISTRANT 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 THE CITY OF SAN ANTONIO, STATE OF TEXAS, ON APRIL 21, 1997.
  
  
  
                                      ILEX ONCOLOGY, INC.
                                      
                                      
                                      
                                      By:    /s/ Richard L. Love               
                                         ---------------------------------------
                                                 Richard L. Love
                                          President and Chief Executive Officer
                                      
  
  
  
  
                                 POWER OF ATTORNEY
  
           KNOW ALL MEN BY THESE PRESENTS, that each individual whose signature
  appears below constitutes and appoints Richard L. Love and James R. Koch, and
  each of them, his true and lawful attorney-in-fact and agent, with full power
  of substitution and resubstitution, for him and in his 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 the same
  and all exhibits thereto, and all documents in connection therewith, with the
  Securities and Exchange Commission, granting said attorney-in-fact and agent,
  and either of them, 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 he might or could do in person, hereby
  ratifying and confirming all that said attorney-in-fact and agent or either of
  them, or their or his substitute or substitutes, 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.
  
  <TABLE>
  <CAPTION>
               Signature                                  Title                              Date
               ---------                                  -----                              ----
        <S>                              <C>                                            <C>
         /s/ Gary V. Woods               Director                                       April 21, 1997
  ------------------------------------                                                                
             Gary V. Woods
  
  
         /s/ Richard L. Love             President, Chief Executive Officer and         April 21, 1997
  ------------------------------------   Director (Principal Executive Officer)                       
            Richard L. Love                                                    
  
  
  
         /s/ Alexander L. Weis, Ph.D.    Director                                       April 21, 1997
  ------------------------------------                                                                
        Alexander L. Weis, Ph.D.
  
         /s/ James R. Koch               Vice President and Chief Financial             April 21, 1997
  ------------------------------------   Officer (Principal Financial and                             
             James R. Koch               Accounting Officer              
                                                                         
  
  
  
         /s/ Daniel D. Von Hoff, M.D.    Director                                       April 21, 1997
  ------------------------------------                                                                
        Daniel D. Von Hoff, M.D.
  </TABLE>
  
  
  
  
  
                                       II-5
  <PAGE>   7
  <TABLE>
     <S>                                 <C>                                            <C>
         /s/ John L. Cassis              Director                                       April 21, 1997
  ------------------------------------                                                                
             John L. Cassis
  
  
         /s/ A. Dana Callow, Jr.         Director                                       April 21, 1997
  ------------------------------------                                                                
          A. Dana Callow, Jr.
  
         /s/ Ruskin C. Norman, M.D.      Director                                       April 21, 1997
  ------------------------------------                                                                
         Ruskin C. Norman, M.D.
  
  
                                         Director
  ------------------------------------           
     Jerry R. Mitchell, M.D., Ph.D.
  
  
        /s/ Jason S. Fisherman, M.D.     Director                                       April 21, 1997
  ------------------------------------                                                                
        Jason S. Fisherman, M.D.
  </TABLE>
  
  
  
  
                                       II-6
  
  <PAGE>   8
                                INDEX TO EXHIBITS
  
  <TABLE>
  <CAPTION>
  EXHIBIT 
  NUMBER      EXHIBIT
  -------     --------
  <S>         <C>
       4.3    Form of Incentive Stock Option Agreement under the 1995 Stock
              Option Plan.
   
       5.1    Opinion of Fulbright & Jaworski L.L.P.
   
      23.1    Consent of Arthur Andersen LLP.
  </TABLE>
metadata_documents: [{"type": "S-8", "sequence": "1", "description": "FORM S-8", "secsgml_size_bytes": 19301}]
metadata_filer: {"company-data": {"conformed-name": "ILEX ONCOLOGY INC", "cik": "0001001915", "assigned-sic": "8071", "irs-number": "742699185", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-25537", "film-number": "97584288"}, "business-address": {"street1": "11550 IH-10 WEST SUITE 300", "city": "SAN ANTONIO", "state": "TX", "zip": "78230", "phone": "2106776080"}, "mail-address": {"street1": "14785 OMICRON DR SUITE 101", "city": "SAN ANTONIO", "state": "TX", "zip": "78245"}}
text: 1
       As filed with the Securities and Exchange Commission on April 21, 1997
  
                                                             Registration No. 333-
  
  ================================================================================
  
                         SECURITIES AND EXCHANGE COMMISSION
                               WASHINGTON, D.C. 20549
  
                            -------------------------
  
                                      FORM S-8
  
              REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933
  
                            -------------------------
  
                                ILEX ONCOLOGY, INC.
               (Exact name of registrant as specified in its charter)
  
                  DELAWARE                                   74-2699185
       (State or other jurisdiction of        (I.R.S. Employer Identification No.)
       incorporation or organization)             
                                               
                                               
           11550 IH 10 WEST, SUITE 300           
               SAN ANTONIO, TEXAS                              78230
     (Address of Principal Executive Offices)                (Zip Code)
                                       
       
  
                     ILEX ONCOLOGY, INC. 1995 STOCK OPTION PLAN
  
                   ILEX ONCOLOGY, INC. 1996 NON-EMPLOYEE DIRECTOR
                                 STOCK OPTION PLAN
                             (Full title of the plans)
  
                                  RICHARD L. LOVE
                                   PRESIDENT AND
                              CHIEF EXECUTIVE OFFICER
                                ILEX ONCOLOGY, INC.
                            11550 IH 10 WEST, SUITE 300
                             SAN ANTONIO, TEXAS  78230
                      (Name and address of agent for service)
  
                                   (210) 949-8200
           (Telephone number, including area code, of agent for service)
  
                            -------------------------
  
                                   With Copy to:
  
                            Fulbright & Jaworski L.L.P.
                           300 Convent Street, Suite 2200
                              San Antonio, Texas 78205
                                   (210) 224-5575
                            Attention: Phillip M. Renfro
  
                            -------------------------
  
                          CALCULATION OF REGISTRATION FEE
  ==========================================================================================================================
                                                                                              Proposed       
                                                                      Proposed Maximum        Maximum            Amount of
         Title of Securities to be                                   Offering Price Per      Aggregate         Registration
                Registered                Amount to be registered        Share (1)         Offering Price (1)      Fee
  --------------------------------------------------------------------------------------------------------------------------
  Common Stock,  $.01 par value . . .        1,313,078 shares             $12.32           $16,177,121         $4,903
  --------------------------------------------------------------------------------------------------------------------------
   Total . . . . . . . . . . . . . . .                                                      $16,177,121         $4,903
  ==========================================================================================================================
  (1)      Estimated in accordance with Rule 457(c) and (h) solely for the
           purpose of calculating the registration fee on the basis of the
           average of the high and low prices of the Common Stock as reported by
           the National Market System of NASDAQ on April 16, 1997.
  
  ================================================================================
  2
                                      PART II
  
                 INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  
  ITEM 3.        INCORPORATION OF DOCUMENTS BY REFERENCE.
  
                 The following documents are hereby incorporated by reference in
  this Registration Statement:
  
                 1.       The prospectus of ILEX Oncology, Inc., a Delaware
  corporation (the "Registrant" or the "Company"), filed with Registration
  Statement No. 333-17769 pursuant to Rule 424(b) under the Securities of 1933,
  as amended (the "Securities Act"), which contains audited financial statements
  of the Registrant for the fiscal year ended December 31, 1996;
  
                 2.       All other reports filed pursuant to Section 13(a) or
  15(d) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"),
  since the effective date of the Registration Statement No. 333-17769; and
  
                 3.       The description of the Registrant's common stock, $.01
  par value (the "Common Stock"), set forth under the caption "Description of the
  Registrant's Securities to be Registered" contained in the Registrant's Form
  8-A, filed by the Registrant with the Securities Exchange Commission pursuant
  to the Exchange Act on February 11, 1997.
  
                 All documents filed by the Registrant pursuant to Sections
  13(a), 13(c), 14 and 15(d) of the Exchange Act subsequent to the date of the
  filing hereof and prior to the filing of a post-effective amendment which
  indicates that all securities offered 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 documents.
  
  ITEM 4.        DESCRIPTION OF SECURITIES.
  
                 Not applicable.
  
  ITEM 5.        INTERESTS OF NAMED EXPERTS AND COUNSEL.
  
                 Not applicable.
  
  ITEM 6.        INDEMNIFICATION OF DIRECTORS AND OFFICERS.
  
                 Section 145 of the Delaware General Corporation Law empowers the
  Registrant to, and the Bylaws of the Registrant provide that it shall,
  indemnify any person who was or is a party or is threatened to be made a party
  to any threatened, pending or completed action, suit or proceeding by reason of
  the fact that he is or was a director, officer, employee or agent of the
  Registrant, or is or was serving at the
  
                                        II-1
  3
  request of the Registrant as a director, officer, employee or agent of another
  corporation, partnership, joint venture, trust or other enterprise, against
  expenses, judgments, fines and amounts paid in settlement actually and
  reasonably incurred by him in connection with such action, suit or proceeding
  if he acted in good faith and in a manner he reasonably believed to be in or
  not opposed to the best interest of the Registrant, and, with respect to any
  criminal action or proceeding, had no reasonable cause to believe his conduct
  was unlawful; except that, in the case of an action or suit by or in the right
  of the Registrant, no indemnification may be made in respect of any claim,
  issue or matter as to which such person shall have been adjudged to be liable
  for negligence or misconduct in the performance of his duty to the Registrant
  unless and only to the extent that the Court of Chancery or the court in which
  such action or suit was brought shall determine that such person is fairly and
  reasonably entitled to indemnity for proper expenses.
  
  ITEM 7.        EXEMPTION FROM REGISTRATION CLAIMED.
  
                 Not applicable.
  
  ITEM 8.        EXHIBITS.
  
       3.1    Amended and Restated Certificate of Incorporation of the Company
              (incorporated by reference to Exhibit 3.1 of the Company's
              Registration Statement on Form S-1, as amended (Reg. No.
              333-17769)).
  
       3.2    Bylaws of the Company, as amended (incorporated by reference to
              Exhibit 3.2 of the Company's Registration Statement on Form S-1, as
              amended (Reg. No. 333-17769)).
  
       4.1    Specimen Common Stock Certificate (incorporated by reference to
              Exhibit 4.1 of the Company's Registration Statement on Form S-1, as
              amended (Reg. No. 333-17769)).
  
       4.2    ILEX Oncology, Inc. 1995 Stock Option Plan (incorporated by
              reference to Exhibit 10.47 of the Company's Registration Statement
              on Form S-1, as amended (Reg. No. 333-17769)).
  
  *    4.3    Form of Incentive Stock Option Agreement under the 1995 Stock
              Option Plan.
  
       4.4    ILEX Oncology, Inc. 1996 Non-Employee Director Stock Option Plan
              (incorporated by reference to Exhibit 10.48 of the Company's
              Registration Statement on Form S-1, as amended (Reg. No.
              333-17769)).
  
       4.5    Form of Non-Employee Director Stock Option Agreement under the 1996
              Non-Employee Director Stock Option Plan (incorporated by reference
              to Exhibit 10.49 of the Company's Registration Statement on Form
              S-1, as amended (Reg. No. 333-17769)).
  
  *    5.1    Opinion of Fulbright & Jaworski L.L.P.
  
                                        II-2
  4
  *   23.1    Consent of Arthur Andersen LLP.
  
  *   23.3    Consent of Fulbright & Jaworski L.L.P. (included in  Exhibit 5.1).
  
  *   24.1    Powers of Attorney from certain members of the Board of Directors
              of the Company (included at II-5).  
  
  --------------------
  
  *           Filed herewith.
  
  ITEM 9.     UNDERTAKINGS.
  
                 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 facts or
                          events arising after the effective date of this
                          Registration Statement (or the most recent
                          post-effective amendment hereof) which, individually or
                          in the aggregate, represent a fundamental change in the
                          information set forth in this Registration Statement;
                          and
  
                          (iii)   To include any material information with
                          respect to the plan of distribution not previously
                          disclosed in this Registration Statement or any
                          material change to such information in this
                          Registration Statement;
  
                 provided, however, that paragraphs (i) and (ii) do not apply if
                 the information required to be included in a post-effective
                 amendment by those paragraphs is contained in periodic reports
                 filed by the Registrant pursuant to Section 13 or Section 15(d)
                 of the Exchange Act of 1934 that are incorporated by reference
                 in this 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 herein, and the offering of such
                 securities at that time shall be deemed to be the initial bona
                 fide offering thereof.
  
                 (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.
  
                 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 Section 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 this
  
                                        II-3
  5
  Registration Statement shall be deemed to be a new registration statement
  relating to the securities offered herein, and the offering of such securities
  at that time shall be deemed to be the initial bona fide offering thereof.
  
                 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.
  
                                        II-4
  6
                                     SIGNATURES
  
          PURSUANT TO THE REQUIREMENTS OF THE SECURITIES ACT, AS AMENDED, THE
  REGISTRANT 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 THE CITY OF SAN ANTONIO, STATE OF TEXAS, ON APRIL 21, 1997.
  
                                      ILEX ONCOLOGY, INC.
                                      
                                      
                                      
                                      By:    /s/ Richard L. Love               
                                         ---------------------------------------
                                                 Richard L. Love
                                          President and Chief Executive Officer
                                      
  
                                 POWER OF ATTORNEY
  
           KNOW ALL MEN BY THESE PRESENTS, that each individual whose signature
  appears below constitutes and appoints Richard L. Love and James R. Koch, and
  each of them, his true and lawful attorney-in-fact and agent, with full power
  of substitution and resubstitution, for him and in his 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 the same
  and all exhibits thereto, and all documents in connection therewith, with the
  Securities and Exchange Commission, granting said attorney-in-fact and agent,
  and either of them, 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 he might or could do in person, hereby
  ratifying and confirming all that said attorney-in-fact and agent or either of
  them, or their or his substitute or substitutes, 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/ Gary V. Woods               Director                                       April 21, 1997
  ------------------------------------                                                                
             Gary V. Woods
  
         /s/ Richard L. Love             President, Chief Executive Officer and         April 21, 1997
  ------------------------------------   Director (Principal Executive Officer)                       
            Richard L. Love                                                    
  
         /s/ Alexander L. Weis, Ph.D.    Director                                       April 21, 1997
  ------------------------------------                                                                
        Alexander L. Weis, Ph.D.
  
         /s/ James R. Koch               Vice President and Chief Financial             April 21, 1997
  ------------------------------------   Officer (Principal Financial and                             
             James R. Koch               Accounting Officer              
                                                                         
  
         /s/ Daniel D. Von Hoff, M.D.    Director                                       April 21, 1997
  ------------------------------------                                                                
        Daniel D. Von Hoff, M.D.
  II-5
  7
  /s/ John L. Cassis              Director                                       April 21, 1997
  ------------------------------------                                                                
             John L. Cassis
  
         /s/ A. Dana Callow, Jr.         Director                                       April 21, 1997
  ------------------------------------                                                                
          A. Dana Callow, Jr.
  
         /s/ Ruskin C. Norman, M.D.      Director                                       April 21, 1997
  ------------------------------------                                                                
         Ruskin C. Norman, M.D.
  
                                         Director
  ------------------------------------           
     Jerry R. Mitchell, M.D., Ph.D.
  
        /s/ Jason S. Fisherman, M.D.     Director                                       April 21, 1997
  ------------------------------------                                                                
        Jason S. Fisherman, M.D.
  II-6
  8
                                INDEX TO EXHIBITS
  EXHIBIT 
  NUMBER      EXHIBIT
  -------     --------
  4.3    Form of Incentive Stock Option Agreement under the 1995 Stock
              Option Plan.
   
       5.1    Opinion of Fulbright & Jaworski L.L.P.
   
      23.1    Consent of Arthur Andersen LLP.