<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2005-01-19</periodOfReport>

    <issuer>
        <issuerCik>0000104889</issuerCik>
        <issuerName>WASHINGTON POST CO</issuerName>
        <issuerTradingSymbol>WPO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001192668</rptOwnerCik>
            <rptOwnerName>OLSON RONALD L</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>MUNGER, TOLLES &amp; OLSON LLP</rptOwnerStreet1>
            <rptOwnerStreet2>355 SOUTH GRAND AVENUE, 35TH FLOOR</rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90071-1560</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Class B Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2005-01-19</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>300</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>910.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>300</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>Living Trust</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes></footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Ronald L. Olson by Diana M. Daniels</signatureName>
        <signatureDate>2005-01-20</signatureDate>
    </ownerSignature>
</ownershipDocument>
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X0202
4
2005-01-19
0000104889
WASHINGTON POST CO
WPO
0001192668
OLSON RONALD L
MUNGER, TOLLES & OLSON LLP
355 SOUTH GRAND AVENUE, 35TH FLOOR
LOS ANGELES
CA
90071-1560
1
0
0
0
Class B Common Stock
2005-01-19
4
P
0
300
910.00
A
300
I
Living Trust
Ronald L. Olson by Diana M. Daniels
2005-01-20