<SEC-DOCUMENT>0001209191-17-050733.txt : 20170830
<SEC-HEADER>0001209191-17-050733.hdr.sgml : 20170830
<ACCEPTANCE-DATETIME>20170830164338
ACCESSION NUMBER:		0001209191-17-050733
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20170828
FILED AS OF DATE:		20170830
DATE AS OF CHANGE:		20170830

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			BASKETT FOREST
		CENTRAL INDEX KEY:			0001277631

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-37566
		FILM NUMBER:		171061182

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SYNLOGIC, INC.
		CENTRAL INDEX KEY:			0001527599
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				261824804
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		200 SIDNEY STREET
		STREET 2:		SUITE 320
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139
		BUSINESS PHONE:		617-401-9975

	MAIL ADDRESS:	
		STREET 1:		200 SIDNEY STREET
		STREET 2:		SUITE 320
		CITY:			CAMBRIDGE
		STATE:			MA
		ZIP:			02139

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	Mirna Therapeutics, Inc.
		DATE OF NAME CHANGE:	20110809
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc4.xml
<DESCRIPTION>FORM 4 SUBMISSION
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2017-08-28</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001527599</issuerCik>
        <issuerName>SYNLOGIC, INC.</issuerName>
        <issuerTradingSymbol>SYBX</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001277631</rptOwnerCik>
            <rptOwnerName>BASKETT FOREST</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1954 GREENSPRING DRIVE</rptOwnerStreet1>
            <rptOwnerStreet2>SUITE 600</rptOwnerStreet2>
            <rptOwnerCity>TIMONIUM</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>21093</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>1</isTenPercentOwner>
            <isOther>0</isOther>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeTransaction>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <transactionDate>
                <value>2017-08-28</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3394439</value>
                </transactionShares>
                <transactionPricePerShare>
                    <footnoteId id="F1"/>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>3818940</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>I</value>
                </directOrIndirectOwnership>
                <natureOfOwnership>
                    <value>See Note 2</value>
                    <footnoteId id="F2"/>
                </natureOfOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <footnotes>
        <footnote id="F1">Shares of capital stock of the corporation then known as Synlogic, Inc. (&quot;Old Synlogic&quot;) were converted into shares of the Issuer pursuant to that certain Agreement and Plan of Merger and Reorganization, dated as of May 15, 2017, by and among the Issuer, Meerkat Merger Sub, Inc. and Old Synlogic (the &quot;Merger Agreement&quot;). Pursuant to the terms of the Merger Agreement, each share of capital stock was exchanged for 0.5532 shares of the Issuer's common stock, giving effect to a reverse split of the Issuer's common stock of 7-to-1.</footnote>
        <footnote id="F2">The Reporting Person is a director of NEA 14 GP, LTD, which is the sole general partner of NEA Partners 14, L.P. (&quot;NEA Partners 14&quot;). NEA Partners 14 is the sole general partner of New Enterprise Associates 14, L.P. (&quot;NEA 14&quot;), which is the direct beneficial owner of the securities. The Reporting Person disclaims beneficial ownership, within the meaning of Section 16 of the Securities Exchange Act of 1934, as amended, or otherwise of such portion of the NEA 14 shares in which the Reporting Person has no pecuniary interest.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/ Sasha Keough, attorney-in-fact</signatureName>
        <signatureDate>2017-08-30</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
