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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
 GlakgQ6t1RSkMRRsZlDW+FEa/kOT8J7XfrxMLp7wnGtcNYxsclb89zRkPK1EmDZb
 V5Au2Awv0l/DGzUdgRgNiw==

<SEC-DOCUMENT>0001241921-08-000018.txt : 20080312
<SEC-HEADER>0001241921-08-000018.hdr.sgml : 20080312
<ACCEPTANCE-DATETIME>20080312175350
ACCESSION NUMBER:		0001241921-08-000018
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080310
FILED AS OF DATE:		20080312
DATE AS OF CHANGE:		20080312

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:			SANNINO LOUIS J
		CENTRAL INDEX KEY:			0001199546

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-08430
		FILM NUMBER:		08684451

	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>2008-03-10</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001199546</rptOwnerCik>
            <rptOwnerName>SANNINO LOUIS J</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>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>EVP, Human Resources</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2008-03-10</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>60000</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>148772</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>16762</value>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>401 (K) Shares</value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The stock was sold in multiple transactions at the following prices:  600 @ 49.15; 300 @ 49.17; 700 @ 49.18; 1400 @ 49.23; 700 @ 49.25; 900 @ 49.26; 900 @ 49.27; 200 @ 49.28; 1700 @ 49.29; 2225 @ 49.30; 575 @ 49.31; 2400 @ 49.32; 2000 @ 49.33; 900 @ 49.34; 1100 @ 49.35; 200 @ 49.36; 800 @ 49.37; 1800 @ 49.38; 800 @ 49.40; 400 @ 49.41; 2100 @ 49.45; 100 @ 49.46; 300 @ 49.48; 1900 @ 49.49; 1800 @ 49.50; 700 @ 49.51; 1200 @ 49.52; 1145 @ 49.53; 400 @ 49.54; 1300 @ 49.55; 600 @ 49.555; 1400 @ 49.56; 2200 @ 49.57; 2300 @ 49.58; 2700 @ 49.59; 1900 @ 49.60; 1099 @ 49.61; 355 @ 49.62; 600 @ 49.63; 1201 @ 49.64; 1200 @ 49.66; 400 @ 49.71; 100 @ 49.72; 400 @ 49.74; 700 @ 49.75; 900 @ 49.80; 100 @ 49.81; 700 @ 49.82; 700 @ 49.83; 400 @ 49.86; 100 @ 49.87; 100 @ 49.88; 400 @ 49.89; 600 @ 49.91; 300 @ 49.93; 900 @ 49.94; 300 @ 49.96; 500 @ 49.98; 1800 @ 50.00; 2300 @ 50.01; 300 @ 50.02; 100 @ 50.04; 200 @ 50.07; 300 @ 50.13 and 300 @ 50.17.</footnote>
        <footnote id="F2">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="F3">Based upon units held in 401K Plan and the fair market value of MDR common stock as of March 10, 2008.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Liane K. Hinrichs, by Power of Attorney</signatureName>
        <signatureDate>2008-03-12</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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