-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 ccAsMp8FVKREDiQ5UyTatw==

<SEC-DOCUMENT>0001181431-04-059303.txt : 20041216
<SEC-HEADER>0001181431-04-059303.hdr.sgml : 20041216
<ACCEPTANCE-DATETIME>20041216164610
ACCESSION NUMBER:		0001181431-04-059303
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20041215
FILED AS OF DATE:		20041216
DATE AS OF CHANGE:		20041216

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			HYDRIL CO
		CENTRAL INDEX KEY:			0001116030
		STANDARD INDUSTRIAL CLASSIFICATION:	OIL & GAS FILED MACHINERY & EQUIPMENT [3533]
		IRS NUMBER:				952777268
		STATE OF INCORPORATION:			DE

	BUSINESS ADDRESS:	
		STREET 1:		3300 N SAM HOUSTON PKWY E
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77032
		BUSINESS PHONE:		2814492000

	MAIL ADDRESS:	
		STREET 1:		3300 N SAM HOUSTON PKWY EAST
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77032

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			SEAVER CHRISTOPHER T
		CENTRAL INDEX KEY:			0001182500

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-31296
		FILM NUMBER:		041208758

	BUSINESS ADDRESS:	
		STREET 1:		3300 NORTH SAM HOUSTON PKWY EAST
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77032
		BUSINESS PHONE:		2819858712

	MAIL ADDRESS:	
		STREET 1:		3300 NORTH SAM HOUSTON PKWY EAST
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77032-3411
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>rrd61686.xml
<DESCRIPTION>FORM 4:  12-16-04 C. SEAVER
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2004-12-15</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001116030</issuerCik>
        <issuerName>HYDRIL CO</issuerName>
        <issuerTradingSymbol>HYDL</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001182500</rptOwnerCik>
            <rptOwnerName>SEAVER CHRISTOPHER T</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>3300 NORTH SAM HOUSTON PARKWAY EAST</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77032</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>President and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-12-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>17.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>131100</value>
                    <footnoteId id="F6"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common stock</value>
            </securityTitle>
            <transactionDate>
                <value>2004-12-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>47.00</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>111100</value>
                    <footnoteId id="F7"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee stock option (right to buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>17.00</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2004-12-15</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>20000</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F2"/>
            </exerciseDate>
            <expirationDate>
                <value>2010-09-26</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>20000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>43020</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeHolding>
            <securityTitle>
                <value>Class B Common stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <footnoteId id="F4"/>
            </conversionOrExercisePrice>
            <exerciseDate>
                <footnoteId id="F4"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F5"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>111100</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>111100</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeHolding>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">All of the transactions reported on this Form were effected pursuant to a Rule 10b5-1 sales plan initiated on November 8, 2002</footnote>
        <footnote id="F2">The reporting person was granted options to purchase 66,600 shares of Common stock on September 26, 2000, which became exercisable in five equal installments beginning September 26, 2001.  The portion of the options exercised became exercisable on or before September 26, 2004.</footnote>
        <footnote id="F3">Not applicable.</footnote>
        <footnote id="F4">Class B Common stock is convertible at any time by the holder for an equivalent number of shares of Common stock on a one-for-one basis.</footnote>
        <footnote id="F5">There is no applicable expiration date for the Class B Common stock.</footnote>
        <footnote id="F6">Consists of 111,100 shares of Class B Common stock and 20,000 shares of Common stock.  The Class B Common stock is convertible at any time by the holder for an equivalent number of shares of Commmon stock.  Shares of Class B common stock are also reported on Table II.</footnote>
        <footnote id="F7">Consists of shares of Class B Common stock.  The Class B Common stock is convertible at any time by the holder for an equivalent number of shares of Common stock.  Shares of Class B Common stock are also reported on Table II.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Christopher T. Seaver</signatureName>
        <signatureDate>2004-12-16</signatureDate>
    </ownerSignature>
</ownershipDocument>

</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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