<?xml version="1.0"?>
<ownershipDocument>

    <schemaVersion>X0202</schemaVersion>

    <documentType>4</documentType>

    <periodOfReport>2006-11-14</periodOfReport>

    <notSubjectToSection16>0</notSubjectToSection16>

    <issuer>
        <issuerCik>0001289850</issuerCik>
        <issuerName>NeuroMetrix, Inc.</issuerName>
        <issuerTradingSymbol>NURO</issuerTradingSymbol>
    </issuer>

    <reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001297277</rptOwnerCik>
            <rptOwnerName>Daniello Guy</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>C/O NEUROMETRIX, INC.</rptOwnerStreet1>
            <rptOwnerStreet2>62 FOURTH AVENUE</rptOwnerStreet2>
            <rptOwnerCity>WALTHAM</rptOwnerCity>
            <rptOwnerState>MA</rptOwnerState>
            <rptOwnerZipCode>02451</rptOwnerZipCode>
            <rptOwnerStateDescription></rptOwnerStateDescription>
        </reportingOwnerAddress>
        <reportingOwnerRelationship>
            <isDirector>0</isDirector>
            <isOfficer>1</isOfficer>
            <isTenPercentOwner>0</isTenPercentOwner>
            <isOther>0</isOther>
            <officerTitle>Sr.V.P. Information Technology</officerTitle>
        </reportingOwnerRelationship>
    </reportingOwner>

    <derivativeTable>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee Stock Option (right to buy Common Stock)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>2.25</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2006-11-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>D</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1250</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>D</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-06-05</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1250</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>0</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
        <derivativeTransaction>
            <securityTitle>
                <value>Employee Stock Option (right to buy Common Stock)</value>
            </securityTitle>
            <conversionOrExercisePrice>
                <value>4.48</value>
            </conversionOrExercisePrice>
            <transactionDate>
                <value>2006-11-14</value>
            </transactionDate>
            <transactionCoding>
                <transactionFormType>4</transactionFormType>
                <transactionCode>A</transactionCode>
                <equitySwapInvolved>0</equitySwapInvolved>
                <footnoteId id="F1"/>
                <footnoteId id="F2"/>
            </transactionCoding>
            <transactionTimeliness>
                <value></value>
            </transactionTimeliness>
            <transactionAmounts>
                <transactionShares>
                    <value>1250</value>
                </transactionShares>
                <transactionPricePerShare>
                    <value>0</value>
                </transactionPricePerShare>
                <transactionAcquiredDisposedCode>
                    <value>A</value>
                </transactionAcquiredDisposedCode>
            </transactionAmounts>
            <exerciseDate>
                <footnoteId id="F3"/>
            </exerciseDate>
            <expirationDate>
                <value>2013-06-05</value>
            </expirationDate>
            <underlyingSecurity>
                <underlyingSecurityTitle>
                    <value>Common Stock</value>
                </underlyingSecurityTitle>
                <underlyingSecurityShares>
                    <value>1250</value>
                </underlyingSecurityShares>
            </underlyingSecurity>
            <postTransactionAmounts>
                <sharesOwnedFollowingTransaction>
                    <value>1250</value>
                </sharesOwnedFollowingTransaction>
            </postTransactionAmounts>
            <ownershipNature>
                <directOrIndirectOwnership>
                    <value>D</value>
                </directOrIndirectOwnership>
            </ownershipNature>
        </derivativeTransaction>
    </derivativeTable>

    <footnotes>
        <footnote id="F1">The two reported transactions involved an amendment of an outstanding option award, resulting in the deemed cancellation, for purposes of Section 16, of the &quot;old&quot; option and the grant of a &quot;replacement&quot; option.  The existing option was initially granted prior to the company's initial public offering and had an exercise price per share that was less than the fair market value of the company's common stock on the grant date as determined by the company's board of directors.</footnote>
        <footnote id="F2">The company had historically accounted for this option as a discounted option.  Subsequent to the grant of this option, the IRS adopted Section 409A of the Internal Revenue Code, which negatively impacted the tax treatment of discounted stock options.  However, the IRS issued guidance permitting companies and option holders to amend discounted stock options to increase the exercise price to equal the fair market value per share on the grant date in order to avoid application of Section 409A.  Accordingly, the company and the related person agreed to amend the option to increase the exercise price from $2.25 per share to $4.48 per share.</footnote>
        <footnote id="F3">This option was vested 50% as of November 14, 2006 and the remaining 50% will vest on June 5, 2007</footnote>
    </footnotes>

    <ownerSignature>
        <signatureName>/s/ Nicholas J. Alessi, Attorney-in-Fact</signatureName>
        <signatureDate>2006-11-16</signatureDate>
    </ownerSignature>
</ownershipDocument>
