diff --git a/packages/asset-swapper/src/utils/quote_requestor.ts b/packages/asset-swapper/src/utils/quote_requestor.ts
index 3dec05d733..6a6b0fd4eb 100644
--- a/packages/asset-swapper/src/utils/quote_requestor.ts
+++ b/packages/asset-swapper/src/utils/quote_requestor.ts
@@ -83,7 +83,7 @@ export class QuoteRequestor {
         sellTokenAddress: string, // taker token
         assetFillAmount: BigNumber,
         comparisonPrice?: BigNumber,
-        isLastLook: boolean = false,
+        isLastLook?: boolean | undefined,
     ): TakerRequestQueryParams {
         const { buyAmountBaseUnits, sellAmountBaseUnits } =
             marketOperation === MarketOperation.Buy
@@ -111,9 +111,11 @@ export class QuoteRequestor {
             buyTokenAddress,
             sellTokenAddress,
             comparisonPrice: comparisonPrice === undefined ? undefined : comparisonPrice.toString(),
-            isLastLook: isLastLook.toString(),
             protocolVersion: '4',
         };
+        if (isLastLook) {
+            requestParamsWithBigNumbers.isLastLook = isLastLook.toString();
+        }
 
         // convert BigNumbers to strings
         // so they are digestible by axios
diff --git a/packages/asset-swapper/test/quote_requestor_test.ts b/packages/asset-swapper/test/quote_requestor_test.ts
index 18350bfe4a..46a8677d9b 100644
--- a/packages/asset-swapper/test/quote_requestor_test.ts
+++ b/packages/asset-swapper/test/quote_requestor_test.ts
@@ -272,7 +272,6 @@ describe('QuoteRequestor', async () => {
                 comparisonPrice: undefined,
                 takerAddress,
                 txOrigin,
-                isLastLook: 'false',
                 protocolVersion: '4',
             };
             const mockedDefaults = {
@@ -579,7 +578,6 @@ describe('QuoteRequestor', async () => {
                 comparisonPrice: undefined,
                 takerAddress,
                 txOrigin: takerAddress,
-                isLastLook: 'false',
                 protocolVersion: '4',
             };
             const mockedDefaults = {
@@ -688,7 +686,6 @@ describe('QuoteRequestor', async () => {
                 takerAddress,
                 txOrigin: takerAddress,
                 protocolVersion: '4',
-                isLastLook: 'false',
             };
             const mockedDefaults = {
                 requestApiKey: apiKey,
@@ -773,7 +770,6 @@ describe('QuoteRequestor', async () => {
                 comparisonPrice: undefined,
                 takerAddress,
                 txOrigin: takerAddress,
-                isLastLook: 'false',
                 protocolVersion: '4',
             };
             // Successful response