<ownershipDocument>
    <schemaVersion>X0201</schemaVersion>

    <documentType>4</documentType>
<periodOfReport>2003-03-31</periodOfReport>
<notSubjectToSection16>0</notSubjectToSection16>
    <issuer>
        <issuerCik>0000356708</issuerCik>
        <issuerName>FIRST REGIONAL BANCORP</issuerName>
        <issuerTradingSymbol>FRGB</issuerTradingSymbol>
</issuer>
<reportingOwner>
        <reportingOwnerId>
            <rptOwnerCik>0001262619</rptOwnerCik>
            <rptOwnerName>EDWARDS FRED M</rptOwnerName>
        </reportingOwnerId>
        <reportingOwnerAddress>
            <rptOwnerStreet1>1801 CENTURY PARK EAST</rptOwnerStreet1>
            <rptOwnerStreet2></rptOwnerStreet2>
            <rptOwnerCity>LOS ANGELES</rptOwnerCity>
            <rptOwnerState>CA</rptOwnerState>
            <rptOwnerZipCode>90067</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>15000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
<footnoteId id="F1"></footnoteId>
</directOrIndirectOwnership>
</ownershipNature>
</nonDerivativeHolding>
<nonDerivativeTransaction><securityTitle><value>Common Stock</value>
</securityTitle>
<transactionDate><value>2003-12-10</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>P</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>400</value>
</transactionShares>
<transactionPricePerShare><value>28.25</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>650</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>I</value>
<footnoteId id="F2"></footnoteId>
</directOrIndirectOwnership>
<natureOfOwnership><value>By Sandra P. Edwards IRA dated 4/15/85</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeTransaction>
<nonDerivativeTransaction><securityTitle><value>Common Stock</value>
</securityTitle>
<transactionDate><value>2003-03-31</value>
</transactionDate>
<transactionCoding><transactionFormType>4</transactionFormType>
<transactionCode>P</transactionCode>
<equitySwapInvolved>0</equitySwapInvolved>
</transactionCoding>
<transactionAmounts><transactionShares><value>250</value>
</transactionShares>
<transactionPricePerShare><value>12.50</value>
</transactionPricePerShare>
<transactionAcquiredDisposedCode><value>A</value>
</transactionAcquiredDisposedCode>
</transactionAmounts>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>250</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>I</value>
<footnoteId id="F2"></footnoteId>
</directOrIndirectOwnership>
<natureOfOwnership><value>By Sandra P. Edwards IRA dated 4/15/85</value>
</natureOfOwnership>
</ownershipNature>
</nonDerivativeTransaction>
</nonDerivativeTable>
<derivativeTable><derivativeHolding><securityTitle><value>Stock Option (right to buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>11.50</value>
</conversionOrExercisePrice>
<exerciseDate><value>2002-12-31</value>
</exerciseDate>
<expirationDate><value>2012-11-01</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>12500</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>25000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeHolding>
<derivativeHolding><securityTitle><value>Stock Option (right to buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>11.50</value>
</conversionOrExercisePrice>
<exerciseDate><value>2003-12-31</value>
</exerciseDate>
<expirationDate><value>2012-11-01</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>2500</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>25000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeHolding>
<derivativeHolding><securityTitle><value>Stock Option (right to buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>11.50</value>
</conversionOrExercisePrice>
<exerciseDate><value>2004-12-31</value>
</exerciseDate>
<expirationDate><value>2012-11-01</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>2500</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>25000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeHolding>
<derivativeHolding><securityTitle><value>Stock Option (right to buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>11.50</value>
</conversionOrExercisePrice>
<exerciseDate><value>2005-12-31</value>
</exerciseDate>
<expirationDate><value>2012-11-01</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>2500</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>25000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeHolding>
<derivativeHolding><securityTitle><value>Stock Option (right to buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>11.50</value>
</conversionOrExercisePrice>
<exerciseDate><value>2006-12-31</value>
</exerciseDate>
<expirationDate><value>2012-11-01</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>2500</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>25000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeHolding>
<derivativeHolding><securityTitle><value>Stock Option (right to buy)</value>
</securityTitle>
<conversionOrExercisePrice><value>11.50</value>
</conversionOrExercisePrice>
<exerciseDate><value>2007-12-31</value>
</exerciseDate>
<expirationDate><value>2012-11-01</value>
</expirationDate>
<underlyingSecurity><underlyingSecurityTitle><value>Common Stock</value>
</underlyingSecurityTitle>
<underlyingSecurityShares><value>2500</value>
</underlyingSecurityShares>
</underlyingSecurity>
<postTransactionAmounts><sharesOwnedFollowingTransaction><value>25000</value>
</sharesOwnedFollowingTransaction>
</postTransactionAmounts>
<ownershipNature><directOrIndirectOwnership><value>D</value>
</directOrIndirectOwnership>
</ownershipNature>
</derivativeHolding>
</derivativeTable>
<footnotes><footnote id="F1">Beneficially owned by reporting person through the Fred M. Edwards Family Trust.</footnote>
<footnote id="F2">Shares beneficially owned by spouse.  The reporting person disclaims beneficial ownership of these shares and this report shall not be deemed an admission that the reporting person is a beneficial owner of such shares for purposes of Section 16 or as for any other purpose.</footnote>
</footnotes>
<remarks>(3) Power of Attorney filed as Exhibit 24 to reporting person's Form 4, filed 12/5/03.</remarks>
<ownerSignature><signatureName>Elizabeth Thompson, attorney-in-fact for Fred M. Edwards</signatureName>
<signatureDate>2003-12-12</signatureDate>
</ownerSignature>
</ownershipDocument>

