-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
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 gpTTBmvsOfhsz33nJvqevA==

<SEC-DOCUMENT>0001241921-07-000084.txt : 20071003
<SEC-HEADER>0001241921-07-000084.hdr.sgml : 20071003
<ACCEPTANCE-DATETIME>20071003163306
ACCESSION NUMBER:		0001241921-07-000084
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20071001
FILED AS OF DATE:		20071003
DATE AS OF CHANGE:		20071003

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:		071153990

	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>2007-10-01</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>2007-10-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>140000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>4.8333</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>855794</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2007-10-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>140000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>715794</value>
                    <footnoteId id="F4"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>10200</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>4.8333</value>
                <footnoteId id="F6"/>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2007-10-01</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>M</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>140000</value>
                    <footnoteId id="F6"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F7"/>
            </exerciseDate>
            <expirationDate>
                <value>2012-03-06</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>140000</value>
                    <footnoteId id="F6"/>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>318100</value>
                    <footnoteId id="F6"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The 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: 5,300 @ $53.85; 200 @ $54.58; 300 @ $54.62; 200 @ $54.65; 900 @ $54.68; 300 @ $54.70; 900 @ $54.79; 300 @ $54.82; 600 @ $54.86; 600 @ $54.87; 200 @ $54.92; 200 @ $54.92; 600 @ $54.93; 200 @ $54.96; 2,100 @ $54.99; 300 @ $55.01; 600 @ $55.02; 300 @ $55.04; 1,500 @ $55.05; 1,200 @ $55.06; 600 @ $55.07; 300 @ $55.09; 600 @ $55.11; 300 @ $55.12; 1,200 @ $55.13; 300 @ $55.14; 400 @ $55.15; 1,000 @ $55.16; 800 @ $55.17; 300 @ $55.19; 600 @ $55.23; 1,500 @ $55.24; 3,900 @ $55.25; 5,297 @ $55.26; 3,250 @ $55.27; 900 @ $55.28; 1,200 @ $55.29; 1,600 @ $55.30; 500 @ $55.31; 1,500 @ $55.32; 100 @ $55.33; 800 @ $55.34; 1,200 @ $55.35; 600 @ $55.36; 1,600 @ $55.37; 4,900 @ $55.38; 8,800 @ $55.39; 2,761 @ $55.40; 1,800 @ $55.41; 1,750 @ $55.42; 2,450 @ $55.43; 1,100 @ $55.44; 2,518 @ $55.45; 2,949 @ $55.46; 1,760 @ $55.47; 2,106 @ $55.48; 2,473 @ $55.49; 2,100 @ $55.50; 3,144 @ $55.51; continued on footnote no. 3</footnote>
        <footnote id="F3">continued from footnote no. 2; 55 @ $55.52; 1,935 @ $55.53; 1,912 @ $55.54; 1,653 @ $55.55; 1,100 @ $55.56; 2,147 @ $55.57; 1,053 @ $55.58; 2,000 @ $55.59; 800 @ $55.60; 900 @ $55.61; 2,221 @ $55.62; 2,389 @ $55.63; 1,278 @ $55.64; 686 @ $55.65; 1,226 @ $55.66; 1,366 @ $55.67; 1,234 @ $55.68; 2,770 @ $55.69; 1,049 @ $55.70; 1,281 @ $55.71; 995 @ $55.72; 1,939 @ $55.73; 166 @ $55.74; 500 @ $55.76; 1,098 @ $55.77; 1,274 @ $55.78; 600 @ $55.79; 300 @ $55.80; 300 @ $55.81; 1,295 @ $55.82; 1,005 @ $55.83; 30 @ $55.84; 470 @ $55.85; 1,000 @ $55.86; 680 @ $55.87; 1,520  @ $55.88; 400 @ $55.89; 300 @ $55.90; 1,170 @ $55.92; 130 @ $55.93; 300 @ $55.94; 300 @ $55.97; 880 @ $55.98; 1,622 @ $55.99; 1,798 @ $56.00; 1,900 @ $56.01; 600 @ $56.02; 25 @ $56.03; 300 @ $56.04 and  490 @ $56.05;</footnote>
        <footnote id="F4">The reporting person's  ownership of common stock has been adjusted to reflect the 2-for-1 stock split that occurred on September 10, 2007.</footnote>
        <footnote id="F5">Based upon units held in 401K Plan and the fair market value of Common Stock as of October 1, 2007.</footnote>
        <footnote id="F6">This option was originally reported as covering 200,000 at an exercise price $14.50, but has been adjusted to reflect the 3-for-2 stock split that occurred on May 31, 2006 and the 2-for-1 stock split that occurred on September 10, 2007.</footnote>
        <footnote id="F7">This option vested in three equal installments on March 6, 2003, 2004 and 2005.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Robert E. Stumpf, by power of attorney</signatureName>
        <signatureDate>2007-10-03</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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