<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2006-05-10</periodOfReport>

    <dateOfOriginalSubmission>2006-05-15</dateOfOriginalSubmission>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000914329</issuerCik>
        <issuerName>FEI CO</issuerName>
        <issuerTradingSymbol>FEIC</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001231157</rptOwnerCik>
            <rptOwnerName>BERGER STEVEN D</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>5350 NE DAWSON CREEK DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>HILLSBORO</rptOwnerCity>
            <rptOwnerState>OR</rptOwnerState>
            <rptOwnerZipCode>971245793</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Senior Vice President</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2006-05-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1288</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>15046.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2006-05-10</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2192</value>
                    <footnoteId id="F4"/>
                    <footnoteId id="F5"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>17238.00</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Amended to move grant from Table II to Table I; additional changes noted in footnote to column 4.</footnote>
        <footnote id="F2">The original Form 4 filed on May 15, 2006 showed the total grant amount, without netting out the shares that will be withheld to cover withholding taxes. This amendment reflects the actual amount of shares the reporting person will receive after such withholding.</footnote>
        <footnote id="F3">Amount shown reflects the net amount of shares the reporting person is expected to receive upon settlement on vesting of the RSUs, after 35.45% of the granted shares are used to cover withholding taxes. The RSUs will vest in four equal annual installments beginning one year from the grant date until fully vested. On each vesting date the grantee will receive 25% of the granted RSUs less 35.45% of the vested number of shares to cover applicable withholding taxes. The amount used to cover taxes is based on an assumed tax rate; if the assumed rate changes, and the amount of shares the reporting person acquires is different, an updated Form 4 will be filed.</footnote>
        <footnote id="F4">The original Form 4 filed on May 15, 2006 showed the amount the reporting person would have been granted if FEI acheived 100% performance against certain return-on-sales metrics set forth in the 2006 operating plan approved by FEI's board, and did not net out shares that will be withheld to cover withholding taxes. The number set forth in this amendment is based on FEI's acheivement of 159.4% of plan, as determined on February 6, 2007, and reflects the actual amount of shares the reporting person will receive after withholding for taxes.</footnote>
        <footnote id="F5">Amount shown reflects the net amount of shares the reporting person is expected to receive under the terms of FEI's variable compensation plan for FY2006, after a portion of the granted shares are used to cover withholding taxes. The RSUs will vest in four equal annual installments beginning on the date performance against plan was determined, which was February 6, 2007. On the first vesting date, the reporting person will receive 25% of the granted shares (the reporting person will be responsible for paying withholding taxes on those shares). On the second, third and fourth vesting dates, the reporting person will receive 25% of the granted RSUs less 41.65% of the vested number of shares to cover applicable withholding taxes. The amount used to cover taxes is based on an assumed tax rate; if the assumed rate changes, and the amount of shares the reporting person acquires is different, an updated Form 4 will be filed.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>By: Bradley J. Thies, Attorney in Fact</signatureName>
        <signatureDate>2007-02-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
