-----BEGIN PRIVACY-ENHANCED MESSAGE-----
Proc-Type: 2001,MIC-CLEAR
Originator-Name: webmaster@www.sec.gov
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 TWSM7vrzLADbmYQaionwg5sDW3P6oaM5D3tdezXMm7z1T+B+twIDAQAB
MIC-Info: RSA-MD5,RSA,
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 nSHqG3liIQl/VlMuiv+4kw==

<SEC-DOCUMENT>0001177702-08-000023.txt : 20080516
<SEC-HEADER>0001177702-08-000023.hdr.sgml : 20080516
<ACCEPTANCE-DATETIME>20080516165207
ACCESSION NUMBER:		0001177702-08-000023
CONFORMED SUBMISSION TYPE:	4/A
PUBLIC DOCUMENT COUNT:		1
CONFORMED PERIOD OF REPORT:	20080430
FILED AS OF DATE:		20080516
DATE AS OF CHANGE:		20080516

ISSUER:		

	COMPANY DATA:	
		COMPANY CONFORMED NAME:			SAIA INC
		CENTRAL INDEX KEY:			0001177702
		STANDARD INDUSTRIAL CLASSIFICATION:	TRUCKING (NO LOCAL) [4213]
		IRS NUMBER:				481229851
		STATE OF INCORPORATION:			DE
		FISCAL YEAR END:			1231

	BUSINESS ADDRESS:	
		STREET 1:		11465 JOHNS CREEK PARKWAY
		STREET 2:		STE 400
		CITY:			DULUTH
		STATE:			2Q
		ZIP:			30097
		BUSINESS PHONE:		7702325067

	MAIL ADDRESS:	
		STREET 1:		11465 JOHNS CREEK PARKWAY
		STREET 2:		STE 400
		CITY:			DULUTH
		STATE:			2Q
		ZIP:			30097

	FORMER COMPANY:	
		FORMER CONFORMED NAME:	SCS TRANSPORTATION INC
		DATE OF NAME CHANGE:	20020717

REPORTING-OWNER:	

	OWNER DATA:	
		COMPANY CONFORMED NAME:			OLSSON BJORN E
		CENTRAL INDEX KEY:			0001325164

	FILING VALUES:
		FORM TYPE:		4/A
		SEC ACT:		1934 Act
		SEC FILE NUMBER:	000-49983
		FILM NUMBER:		08842995

	BUSINESS ADDRESS:	
		BUSINESS PHONE:		7702325067

	MAIL ADDRESS:	
		STREET 1:		SAIA, INC.
		STREET 2:		11465 JOHNS CREEK PARKWAY, STE 400
		CITY:			DULUTH
		STATE:			2Q
		ZIP:			30097
</SEC-HEADER>
<DOCUMENT>
<TYPE>4/A
<SEQUENCE>1
<FILENAME>doc.xml
<DESCRIPTION>PRIMARY DOCUMENT
<TEXT>
<XML>
<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4/A</documentType>

    <periodOfReport>2008-04-30</periodOfReport>

    <dateOfOriginalSubmission>2008-05-02</dateOfOriginalSubmission>

    <issuer>
        <issuerCik>0001177702</issuerCik>
        <issuerName>SAIA INC</issuerName>
        <issuerTradingSymbol>SAIA</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001325164</rptOwnerCik>
            <rptOwnerName>OLSSON BJORN E</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>11465 JOHNS CREEK PARKWAY, SUITE 400</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>JOHNS CREEK</rptOwnerCity>
            <rptOwnerState>GA</rptOwnerState>
            <rptOwnerZipCode>30097</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>1</isDirector>
            <isOfficer>0</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle></officerTitle>
            <otherText></otherText>
        </reportingOwnerRelationship>
    </reportingOwner>

    <nonDerivativeTable>
        <nonDerivativeHolding>
            <securityTitle>
                <value>Common Stock</value>
            </securityTitle>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>2000</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </nonDerivativeHolding>
    </nonDerivativeTable>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Phantom Stock</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>1</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2008-04-30</value>
            </transactionDate>
            <deemedExecutionDate></deemedExecutionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>3499</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>13.81</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F1"/>
            </exerciseDate>
            <expirationDate>
                <footnoteId id="F1"/>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>3499</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>8758</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The shares of phantom stock become payable in the Company's common stock upon the reporting person's termination of service as a Director.</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>James A. Darby</signatureName>
        <signatureDate>2008-05-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
</XML>
</TEXT>
</DOCUMENT>
</SEC-DOCUMENT>
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