<SEC-DOCUMENT>0001140361-15-021288.txt : 20150521
<SEC-HEADER>0001140361-15-021288.hdr.sgml : 20150521
<ACCEPTANCE-DATETIME>20150521143358
ACCESSION NUMBER:		0001140361-15-021288
CONFORMED SUBMISSION TYPE:	4
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20150521
FILED AS OF DATE:		20150521
DATE AS OF CHANGE:		20150521

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			Emergent BioSolutions Inc.
		CENTRAL INDEX KEY:			0001367644
		STANDARD INDUSTRIAL CLASSIFICATION:	PHARMACEUTICAL PREPARATIONS [2834]
		IRS NUMBER:				141902018
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		400 PROFESSIONAL DR, SUITE 400
		CITY:			GAITHERSBURG
		STATE:			MD
		ZIP:			20879
		BUSINESS PHONE:		240-631-3200

	MAIL ADDRESS:	
		STREET 1:		400 PROFESSIONAL DR, SUITE 400
		CITY:			GAITHERSBURG
		STATE:			MD
		ZIP:			20879

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			Bailey Sue
		CENTRAL INDEX KEY:			0001403769

	FILING VALUES:
		FORM TYPE:		4
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	001-33137
		FILM NUMBER:		15882410

	MAIL ADDRESS:	
		STREET 1:		2273 RESEARCH BLVD, SUITE 400
		CITY:			ROCKVILLE
		STATE:			MD
		ZIP:			20850
</SEC-HEADER>
<DOCUMENT>
<TYPE>4
<SEQUENCE>1
<FILENAME>doc1.xml
<DESCRIPTION>FORM 4
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0306</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2015-05-21</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001367644</issuerCik>
        <issuerName>Emergent BioSolutions Inc.</issuerName>
        <issuerTradingSymbol>EBS</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001403769</rptOwnerCik>
            <rptOwnerName>Bailey Sue</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>400 PROFESSIONAL DR, SUITE 400</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>GAITHERSBURG</rptOwnerCity>
            <rptOwnerState>MD</rptOwnerState>
            <rptOwnerZipCode>20879</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>
                <footnoteId id="F1"/>
            </securityTitle>
            <transactionDate>
                <value>2015-05-21</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionAmounts>
                <transactionShares>
                    <value>9400</value>
                    <footnoteId id="F2"/>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>28500</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeTransaction>
    </nonDerivativeTable>

    <derivativeTable></derivativeTable>

    <footnotes>
        <footnote id="F1">Consists of restricted stock units granted under the Third Amended and Restated Emergent BioSolutions Inc. 2006 Stock Incentive Plan.</footnote>
        <footnote id="F2">These restricted stock units vest in three equal annual installments beginning on the first anniversary of the date of grant, assuming continued service with the company. Each restricted stock unit represents the right of the Reporting Person to receive one share of common stock of Emergent BioSolutions Inc., subject to adjustment as provided in the grant agreement.</footnote>
    </footnotes>

    <remarks></remarks>

    <ownerSignature>
        <signatureName>/s/Eric Burt, attorney-in-fact</signatureName>
        <signatureDate>2015-05-21</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
