<?xml version="1.0"?><ownershipDocument><schemaVersion>X0201</schemaVersion>    <documentType>3</documentType><periodOfReport>2003-08-04</periodOfReport><noSecuritiesOwned>0</noSecuritiesOwned><issuer><issuerCik>0000866609</issuerCik><issuerName>INPUT OUTPUT INC</issuerName>        <issuerTradingSymbol>IO</issuerTradingSymbol></issuer><reportingOwner><reportingOwnerId><rptOwnerCik>0001221972</rptOwnerCik><rptOwnerName>SEITZ JOHN N</rptOwnerName></reportingOwnerId><reportingOwnerAddress><rptOwnerStreet1>12300 PARC CREST DRIVE</rptOwnerStreet1><rptOwnerStreet2></rptOwnerStreet2><rptOwnerCity>STAFFORD</rptOwnerCity><rptOwnerState>TX</rptOwnerState><rptOwnerZipCode>77477</rptOwnerZipCode><rptOwnerStateDescription></rptOwnerStateDescription></reportingOwnerAddress><reportingOwnerRelationship><isDirector>1</isDirector><isOfficer>0</isOfficer><isTenPercentOwner>0</isTenPercentOwner><isOther>0</isOther></reportingOwnerRelationship></reportingOwner><derivativeTable><derivativeHolding><securityTitle><value>Option to purchase common stock</value></securityTitle><conversionOrExercisePrice><value>4.9</value></conversionOrExercisePrice><exerciseDate><value>2004-08-04</value><footnoteId id="F1" /></exerciseDate><expirationDate><value>2014-08-04</value></expirationDate><underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value></underlyingSecurityTitle><underlyingSecurityShares><value>20000</value></underlyingSecurityShares></underlyingSecurity><ownershipNature><directOrIndirectOwnership><value>D</value></directOrIndirectOwnership></ownershipNature></derivativeHolding></derivativeTable><footnotes><footnote id="F1">The option becomes exercisable in three equal annual installments beginning on the first anniversary of the grant date specified in Column 2.</footnote></footnotes><remarks></remarks><ownerSignature><signatureName>/s/ Brad Eastman, Attorney-in-fact</signatureName><signatureDate>2003-08-06</signatureDate></ownerSignature></ownershipDocument>

