<SEC-DOCUMENT>0001093557-19-000259.txt : 20191216
<SEC-HEADER>0001093557-19-000259.hdr.sgml : 20191216
<ACCEPTANCE-DATETIME>20191216211700
ACCESSION NUMBER:		0001093557-19-000259
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20191216
FILED AS OF DATE:		20191216
DATE AS OF CHANGE:		20191216

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			AUGUSTINOS NICHOLAS
		CENTRAL INDEX KEY:			0001238485

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-51222
		FILM NUMBER:		191288471

	MAIL ADDRESS:	
		STREET 1:		754 GRAND VIEW AVENUE
		CITY:			SAN FRANCISCO
		STATE:			CA
		ZIP:			94114

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			DEXCOM INC
		CENTRAL INDEX KEY:			0001093557
		STANDARD INDUSTRIAL CLASSIFICATION:	SURGICAL & MEDICAL INSTRUMENTS & APPARATUS [3841]
		IRS NUMBER:				330857544
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		6340 SEQUENCE DRIVE
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121
		BUSINESS PHONE:		8582000200

	MAIL ADDRESS:	
		STREET 1:		6340 SEQUENCE DRIVE
		CITY:			SAN DIEGO
		STATE:			CA
		ZIP:			92121
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>edgardoc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2019-12-16</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001093557</issuerCik>
        <issuerName>DEXCOM INC</issuerName>
        <issuerTradingSymbol>DXCM</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001238485</rptOwnerCik>
            <rptOwnerName>AUGUSTINOS NICHOLAS</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>6340 SEQUENCE DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>SAN DIEGO</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>92121</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>2019-12-16</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>S</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>1812</value>
                    <footnoteId id="F1"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>206.14</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>5042</value>
                    <footnoteId id="F2"/>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>14362</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>by Trust</value>
                    <footnoteId id="F3"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">On March 1, 2019, Mr. Augustinos adopted a 10b5-1 Plan.  This 10b5-1 Plan allows the orderly disposition of shares owned by Mr. Augustinos.   The sale of shares set forth above were pursuant to the 10b5-1 Plan.</footnote>
        <footnote id="F2">Included in this number are 2,676 restricted stock units which were granted on May 31, 2019 and will vest on the earlier of the one year anniversary of the grant date or the date of DexCom Inc's 2020 Annual Meeting.</footnote>
        <footnote id="F3">Shares are held by the Kirschner/Augustinos Revocable Trust, of which the reporting person is trustee.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>By: Jereme Sylvain For: Nicholas Augustinos</signatureName>
        <signatureDate>2019-12-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
