<SEC-DOCUMENT>0000004281-16-000140.txt : 20160715
<SEC-HEADER>0000004281-16-000140.hdr.sgml : 20160715
<ACCEPTANCE-DATETIME>20160715080411
ACCESSION NUMBER:		0000004281-16-000140
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20160713
FILED AS OF DATE:		20160715
DATE AS OF CHANGE:		20160715

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ALCOA INC.
		CENTRAL INDEX KEY:			0000004281
		STANDARD INDUSTRIAL CLASSIFICATION:	ROLLING DRAWING & EXTRUDING OF NONFERROUS METALS [3350]
		IRS NUMBER:				250317820
		STATE OF INCORPORATION:			PA
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		390 PARK AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022-4608
		BUSINESS PHONE:		2128362732

	MAIL ADDRESS:	
		STREET 1:		390 PARK AVENUE
		CITY:			NEW YORK
		STATE:			NY
		ZIP:			10022-4608

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALCOA INC
		DATE OF NAME CHANGE:	19990105

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	ALUMINUM CO OF AMERICA
		DATE OF NAME CHANGE:	19920703

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			TATA RATAN
		CENTRAL INDEX KEY:			0001066630

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-03610
		FILM NUMBER:		161768546

	MAIL ADDRESS:	
		STREET 1:		C/O TATA INDUSTRIES LTD, BOMBAY HOUSE
		STREET 2:		24, HOMI MODY STREET, BOMBAY 400 001
		CITY:			COUNTRY INDIA
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgar.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2016-07-13</periodOfReport>

    <issuer>
        <issuerCik>0000004281</issuerCik>
        <issuerName>ALCOA INC.</issuerName>
        <issuerTradingSymbol>AA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001066630</rptOwnerCik>
            <rptOwnerName>TATA RATAN</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>390 PARK AVENUE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>NEW YORK,</rptOwnerCity>
            <rptOwnerState>NY</rptOwnerState>
            <rptOwnerZipCode>10022</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2016-07-13</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>P</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>2045</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>10.7248</value>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>62546.3491</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value></value>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">The price reported in column 4 is a weighted average price.  The shares were purchased in multiple transactions at prices ranging from $10.7248 to $10.7250.  The reporting person undertakes to provide to Alcoa Inc., any security holder of Alcoa Inc., or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares purchased at each price within the range set forth in this footnote.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Margaret Lam (Assistant Secretary), by power of attorney</signatureName>
        <signatureDate>2016-07-15</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
