diff --git a/src/ResponseListener.ts b/src/ResponseListener.ts
index 80b2759..767e9a9 100644
--- a/src/ResponseListener.ts
+++ b/src/ResponseListener.ts
@@ -59,9 +59,13 @@ export class ResponseListener {
   }
 
   public listenForResponses(
-    subscriptionId: number,
+    subscriptionId: number | string,
     callback: (functionsResponse: FunctionsResponse) => any,
   ) {
+    if (typeof subscriptionId === 'string') {
+      subscriptionId = Number(subscriptionId)
+    }
+
     this.functionsRouter.on(
       'RequestProcessed',
       (
diff --git a/test/integration/ResponseListener.test.ts b/test/integration/ResponseListener.test.ts
index 29ff1b8..accefb0 100644
--- a/test/integration/ResponseListener.test.ts
+++ b/test/integration/ResponseListener.test.ts
@@ -138,7 +138,8 @@ describe('Functions toolkit classes', () => {
         responseEventEmitter.emit('response')
       }
 
-      functionsListener.listenForResponses(subscriptionId, responseCallback)
+      const subIdString = subscriptionId.toString()
+      functionsListener.listenForResponses(subIdString, responseCallback)
 
       await exampleClient.sendRequest(
         'return Functions.encodeUint256(1)',