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Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
Originator-Key-Asymmetric:
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MIC-Info: RSA-MD5,RSA,
 JKzpirO0QHrjWiw0QLWUdC//niI3qzxe5XBlaEnjtLjRikLREg+FM7qyyTziLhjp
 OsIAZxBEyfncnQ+wVG7+QA==

<SEC-DOCUMENT>0000005768-10-000040.txt : 20101208
<SEC-HEADER>0000005768-10-000040.hdr.sgml : 20101208
<ACCEPTANCE-DATETIME>20101208164131
ACCESSION NUMBER:		0000005768-10-000040
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20101206
FILED AS OF DATE:		20101208
DATE AS OF CHANGE:		20101208

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Grazewski Paul
		CENTRAL INDEX KEY:			0001352965

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-06549
		FILM NUMBER:		101240226

	MAIL ADDRESS:	
		STREET 1:		C/O AMERICAN SCIENCE AND ENGINEERING,INC
		STREET 2:		829 MIDDLESEX TURNPIKE
		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>2010-12-06</periodOfReport>

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

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001352965</rptOwnerCik>
            <rptOwnerName>Grazewski Paul</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>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>SVP</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2010-12-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1250</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>83.46</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>9477</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The price reported is a weighted average price. These shares were sold in multiple transactions at prices ranging from a low of $83.4600 to a high of $83.4780 for an average of $83.4629. 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>2010-12-08</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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