<SEC-DOCUMENT>0000049826-15-000124.txt : 20151111
<SEC-HEADER>0000049826-15-000124.hdr.sgml : 20151111
<ACCEPTANCE-DATETIME>20151110161428
ACCESSION NUMBER:		0000049826-15-000124
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		2
CONFORMED PERIOD OF REPORT:	20151106
FILED AS OF DATE:		20151110
DATE AS OF CHANGE:		20151110

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			ILLINOIS TOOL WORKS INC
		CENTRAL INDEX KEY:			0000049826
		STANDARD INDUSTRIAL CLASSIFICATION:	GENERAL INDUSTRIAL MACHINERY & EQUIPMENT [3560]
		IRS NUMBER:				361258310
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		155 HARLEM AVENUE
		CITY:			GLENVIEW
		STATE:			IL
		ZIP:			60025
		BUSINESS PHONE:		8477247500

	MAIL ADDRESS:	
		STREET 1:		155 HARLEM AVENUE
		CITY:			GLENVIEW
		STATE:			IL
		ZIP:			60025

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			LENNY RICHARD H
		CENTRAL INDEX KEY:			0001139497

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-04797
		FILM NUMBER:		151219100

	MAIL ADDRESS:	
		STREET 1:		ILLINOIS TOOL WORKS INC.
		STREET 2:		3600 WEST LAKE AVE.
		CITY:			GLENVIEW
		STATE:			IL
		ZIP:			60026
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>wf-form4_144719005748898.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-11-06</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0000049826</issuerCik>
        <issuerName>ILLINOIS TOOL WORKS INC</issuerName>
        <issuerTradingSymbol>ITW</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001139497</rptOwnerCik>
            <rptOwnerName>LENNY RICHARD H</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>155 HARLEM AVE.</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GLENVIEW</rptOwnerCity>
            <rptOwnerState>IL</rptOwnerState>
            <rptOwnerZipCode>60025</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2015-11-06</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>366</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>92.62</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3779</value>
                    <footnoteId id="F2"/>
                    <footnoteId id="F3"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Represents shares of common stock acquired pursuant to the Illinois Tool Works Inc. 2015 Long-Term Incentive Plan representing quarterly director fees.</footnote>
        <footnote id="F2">Includes 2,772 shares of deferred stock under the ITW Directors' Deferred Fee Plan as of November 6, 2015.</footnote>
        <footnote id="F3">8 shares owned jointly with his spouse and 1,000 shares are held as tenants in common with his spouse through revocable trusts.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>Richard H. Lenny by Janet O. Love, Deputy General Counsel &amp; Assistant Secretary, Attorney-in-Fact POA on file</signatureName>
        <signatureDate>2015-11-10</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
<DOCUMENT>
<TYPE>EX-24
<SEQUENCE>2
<FILENAME>ex-24.htm
<DESCRIPTION>POWER OF ATTORNEY- LENNY
<TEXT>
<!-- Document created using WebFilings -->
<html>
<body>
<pre>
The undersigned hereby constitutes and appoints each of E. Scott Santi, Michael M. Larsen, and Janet O. Love signing singly, his true and lawful attorney-in-fact to:

(1)    execute for and on behalf of the undersigned Forms 3, 4 and 5 in accordance with Section 16(a) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), and the rules thereunder;

(2)    do and perform any and all acts for and on behalf of the undersigned which may be necessary or desirable to complete the execution of any such Form 3, 4 or 5 and the timely filing of such form with the United States Securities and Exchange Commission ("SEC") and any other person; and

(3)    take any other action of any type whatsoever in connection with the foregoing which, in the opinion of such attorney-in-fact, may be of benefit to, in the best interest of, or legally required by, the undersigned, it being understood that the documents executed by such attorney-in-fact on behalf of the undersigned pursuant to this Power of Attorney shall be in such form and shall contain such terms and conditions as such attorney-in-fact may approve in his discretion.

The undersigned acknowledges that the foregoing attorneys-in-fact, in serving in such capacity at the request of the undersigned, are not assuming any of the undersigned's responsibilities to comply with Section 16 of the Exchange Act.

This Power of Attorney shall be effective on the date set forth below and shall continue in full force and effect until the date on which the undersigned shall cease to be subject to Section 16 of the Exchange Act and the rules thereunder or until such earlier date on which written notification executed by the undersigned is filed with the SEC expressly revoking this Power of Attorney.

IN WITNESS WHEREOF, the undersigned has caused this Power of Attorney to be executed as of this 30th day of October 2015.



/s/Richard H. Lenny
Richard H. Lenny

Signed and sworn to before me on
this 30th day of October 2015.

/s/Meghan P. Callero
Notary Public
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
