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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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MIC-Info: RSA-MD5,RSA,
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 jFYo2RmG1lNjqkZhfB/U1w==

<SEC-DOCUMENT>0000005768-10-000043.txt : 20101223
<SEC-HEADER>0000005768-10-000043.hdr.sgml : 20101223
<ACCEPTANCE-DATETIME>20101223143743
ACCESSION NUMBER:		0000005768-10-000043
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20101223
FILED AS OF DATE:		20101223
DATE AS OF CHANGE:		20101223

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			FABIANO ANTHONY R
		CENTRAL INDEX KEY:			0001263158

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-06549
		FILM NUMBER:		101271952

	MAIL ADDRESS:	
		STREET 1:		829 MIDDLESEX TURNPIKE
		STREET 2:		C/O AS&E
		CITY:			BILLERICA
		STATE:			MA
		ZIP:			01821

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			AMERICAN SCIENCE & ENGINEERING, INC.
		CENTRAL INDEX KEY:			0000005768
		STANDARD INDUSTRIAL CLASSIFICATION:	X-RAY APPARATUS & TUBES & RELATED IRRADIATION APPARATUS [3844]
		IRS NUMBER:				042240991
		STATE OF INCORPORATION:			MA
		FISCAL YEAR END:			0331

	BUSINESS ADDRESS:	
		STREET 1:		C/O AS&E
		STREET 2:		829 MIDDLESEX TURNPIKE
		CITY:			BILLERICA
		STATE:			MA
		ZIP:			01821
		BUSINESS PHONE:		9782628700

	MAIL ADDRESS:	
		STREET 1:		C/O AS&E
		STREET 2:		829 MIDDLESEX TURNPIKE
		CITY:			BILLERICA
		STATE:			MA
		ZIP:			01821

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	AMERICAN SCIENCE & ENGINEERING INC
		DATE OF NAME CHANGE:	19920703
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0303</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2010-12-23</periodOfReport>

    <issuer>
        <issuerCik>0000005768</issuerCik>
        <issuerName>AMERICAN SCIENCE &amp; ENGINEERING, INC.</issuerName>
        <issuerTradingSymbol>ASEI</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001263158</rptOwnerCik>
            <rptOwnerName>FABIANO ANTHONY R</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>AMERICAN SCIENCE AND ENGINEERING, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>829 MIDDLESEX TURNPIKE</rptOwnerStreet2>
            <rptOwnerCity>BILLERICA</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>01821</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>CEO</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-12-23</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>3652</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>85.69</value>
                    <footnoteId id="F2"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>63466</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on September 13, 2010.</footnote>
        <footnote id="F2">The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from a low of $85.00 to a high of $86.09 for an average of $85.6888. The reporting person undertakes to provide to American Science and Engineering, Inc., any security holder of American Science and Engineering, Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the ranges set forth in this footnote to this Form 4.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>M. Colette Cooke</signatureName>
        <signatureDate>2010-12-23</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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