-----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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 o3imolJ+qCpxczxVmFB36Q==

<SEC-DOCUMENT>0001241921-07-000078.txt : 20070906
<SEC-HEADER>0001241921-07-000078.hdr.sgml : 20070906
<ACCEPTANCE-DATETIME>20070906164925
ACCESSION NUMBER:		0001241921-07-000078
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20070904
FILED AS OF DATE:		20070906
DATE AS OF CHANGE:		20070906

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			MCDERMOTT INTERNATIONAL INC
		CENTRAL INDEX KEY:			0000708819
		STANDARD INDUSTRIAL CLASSIFICATION:	FABRICATED PLATE WORK (BOILER SHOPS) [3443]
		IRS NUMBER:				720593134
		STATE OF INCORPORATION:			R1
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		777 N. ELDRIDGE PARKWAY
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77079
		BUSINESS PHONE:		281-870-5000

	MAIL ADDRESS:	
		STREET 1:		777 N. ELDRIDGE PARKWAY
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77079

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			WILKINSON BRUCE W
		CENTRAL INDEX KEY:			0001199548

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08430
		FILM NUMBER:		071103142

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		2818705000

	MAIL ADDRESS:	
		STREET 1:		777 N ELDRIDGE PARKWAY
		CITY:			HOUSTON
		STATE:			TX
		ZIP:			77079
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2007-09-04</periodOfReport>

    <issuer>
        <issuerCik>0000708819</issuerCik>
        <issuerName>MCDERMOTT INTERNATIONAL INC</issuerName>
        <issuerTradingSymbol>MDR</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001199548</rptOwnerCik>
            <rptOwnerName>WILKINSON BRUCE W</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O MCDERMOTT INTERNATIONAL, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>777 N. ELDRIDGE PARKWAY</rptOwnerStreet2>
            <rptOwnerCity>HOUSTON</rptOwnerCity>
            <rptOwnerState>TX</rptOwnerState>
            <rptOwnerZipCode>77079</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Chairman and CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-09-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>70000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>9.6666</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>427897</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-09-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>70000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                    <footnoteId id="F4"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>357897</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5100</value>
                    <footnoteId id="F5"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>401 K Plan</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Stock Option (Right to Buy)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>9.6666</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-09-04</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>70000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F6"/>
            </exerciseDate>
            <expirationDate>
                <value>2012-03-06</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>70000</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>229050</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">This sale and underlying exercise reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on March 6, 2007.</footnote>
        <footnote id="F2">The stock was sold in multiple transactions at the following prices: 500 @ $94.59; 200 @ $94.62; 200 @ $94.70; 100 @ $94.71; 200 @ $94.73; 900 @ $94.75; 400 @ $94.79; 900 @ $94.80; 300 @ $94.81; 600 @ $94.83; 300 @ $94.84; 900 @ $94.85; 1100 @ $94.87; 1100 @ $94.88; 1100 @ $94.89; 700 @ $94.90; 606 @ $94.91; 900 @ $94.92; 1100 @ $94.93; 100 @ $94.94; 100 @ $94.95; 800 @ $94.96; 700 @ $94.97; 400 @ $94.98; 600 @ $95.02; 100 @ $95.03; 400 @ $95.05; 500 @ $95.06; 100 @ $95.08; 200 @ $95.15; 200 @ $95.16; 600 @ $95.31; 700 @ $95.32; 100 @ $95.34; 200 @ $95.40; 500 @ $95.41; 100 @ $95.42; 100 @ $95.43; 300 @ $95.46; 244 @ $95.48; 350 @ $95.49; 300 @ $95.50; 200 @ $95.51; 400 @ $95.52; 200 @ $95.53; 800 @ $95.56; 2900 @ $95.58; 500 @ $95.59; 600 @ $95.60; 500 @ $95.61; 800 @ $95.63; 700 @ $95.64; 300 @ $95.66; 700 @ $95.68; 100 @ $95.69; 100 @ $95.70; 200 @ $95.71; 1100 @ $95.72; 296 @ $95.73; 1300 @ $95.74; 500 @ $95.75; continued on footnote no. 3</footnote>
        <footnote id="F3">continued from footnote no. 2; 900 @ $95.76; 1000 @ $95.77; 1100 @ $95.78; 1100 @ $95.79; 700 @ $95.80; 500 @ $95.81; 500 @ $95.82; 1100 @ $95.83; 1100 @ $95.84; 1004 @ $95.85; 800 @ $95.86; 400 @ $95.87; 300 @ $95.88; 1500 @ $95.89; 1000 @ $95.90; 500 @ $95.91; 700 @ $95.92; 600 @ $95.93; 600 @ $95.94; 400 @ $95.95; 200 @ $95.96; 200 @ $95.97; 5500 @ $95.99; 300 @ $96.08; 200 @ $96.09; 600 @ $96.10; 200 @ $96.11; 500 @ $96.12; 300 @ $96.14; 500 @ $96.15; 500 @ $96.16; 100 @ $96.17; 100 @ $96.19; 100 @ $96.20; 100 @ $96.24; 100  @ $96.27; 300 @ $96.28; 400 @ $96.30; 200 @ $96.34; 300 @ $96.37; 200 @ $97.38; 200 @ $96.40; 300 @ $96.41; 200 @ $96.42; 600 @ $96.43; 200 @ $96.44; 100 @ $96.45; 100 @ $96.47; 200 @ $96.48; 200 @ $96.49; 400 @ $96.51; 200 @ $96.53; 300 @ $96.54; 200 @ $96.55; 100 @ $96.59; 200 @ $96.60; 100 @ $96.63; 100 @ $96.67; 600 @ $96.68; 600 @ $96.69; 300 @ $96.70; 200 @ $96.71; 600 @ $96.73; 400 @ $96.74; 500 @ $96.75; 300 @ $96.76; continuted on footnote no. 4</fo
otnote>
        <footnote id="F4">continued from footnote no. 3; 1003 @ $96.77; 97 @ $96.78; 300 @ $96.79; 100 @ $96.80; 400 @ $96.87; 100 @ $96.88; 100 @ $96.90; 300 @ $96.92; 300 @ $96.93; 100 @ $96.94; 100 @ $96.95; 300 @ $96.97; 200 @ $96.98; 600 @ $96.99 and 100 @ $97.00.</footnote>
        <footnote id="F5">Based upon units held in 401K Plan and the fair market value of Common Stock as of September 4, 2007.</footnote>
        <footnote id="F6">This option vested in three equal installments on March 6, 2003, 2004 and 2005.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Liane K. Hinrichs, by power of attorney</signatureName>
        <signatureDate>2007-09-06</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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