diff --git a/lib/main.js b/lib/main.js
index e5f71f0..8752968 100644
--- a/lib/main.js
+++ b/lib/main.js
@@ -30,6 +30,7 @@ const { createNamespace } = require('continuation-local-storage')
 const {
   LambdaClient,
   CreateFunctionCommand,
+  ListEventSourceMappingsCommand,
   GetFunctionCommand,
   UpdateFunctionCodeCommand,
   UpdateFunctionConfigurationCommand
@@ -766,16 +767,12 @@ they may not work as expected in the Lambda environment.
     return this._zip(program, codeDirectory)
   }
 
-  _listEventSourceMappings (lambda, params) {
-    return new Promise((resolve, reject) => {
-      lambda.listEventSourceMappings(params, (err, data) => {
-        if (err) return reject(err)
-        if (data && data.EventSourceMappings) {
-          return resolve(data.EventSourceMappings)
-        }
-        return resolve([])
-      })
-    })
+  async _listEventSourceMappings (lambda, params) {
+    const data = await lambda.send(new ListEventSourceMappingsCommand(params))
+    if (data && data.EventSourceMappings) {
+      return data.EventSourceMappings
+    }
+    return []
   }
 
   _getStartingPosition (eventSource) {
@@ -1009,7 +1006,7 @@ they may not work as expected in the Lambda environment.
         FunctionName: params.FunctionName
       }).promise().then(() => {
         // Function exists
-        return this._listEventSourceMappings(lambda, {
+        return this._listEventSourceMappings(lambdaClient, {
           FunctionName: params.FunctionName
         }).then((existingEventSourceList) => {
           return Promise.all([
diff --git a/test/main.js b/test/main.js
index 23b37f9..4f60a85 100644
--- a/test/main.js
+++ b/test/main.js
@@ -20,6 +20,7 @@ const { mockClient } = require('aws-sdk-client-mock')
 const {
   LambdaClient,
   CreateFunctionCommand,
+  ListEventSourceMappingsCommand,
   GetFunctionCommand,
   UpdateFunctionCodeCommand,
   UpdateFunctionConfigurationCommand
@@ -175,6 +176,7 @@ describe('lib/main', function () {
     mockLambdaClient.on(GetFunctionCommand).resolves(lambdaMockSettings.getFunction)
     mockLambdaClient.on(UpdateFunctionCodeCommand).resolves(lambdaMockSettings.updateFunctionCode)
     mockLambdaClient.on(UpdateFunctionConfigurationCommand).resolves(lambdaMockSettings.updateFunctionConfiguration)
+    mockLambdaClient.on(ListEventSourceMappingsCommand).resolves(lambdaMockSettings.listEventSourceMappings)
   })
   after(() => {
     _awsRestore()
@@ -1358,7 +1360,7 @@ describe('lib/main', function () {
   describe('_listEventSourceMappings', () => {
     it('simple test with mock', () => {
       return lambda._listEventSourceMappings(
-        awsLambda,
+        lambdaClient,
         { FunctionName: 'test-func' }
       ).then((results) => {
         assert.deepEqual(