diff --git a/index.d.ts b/index.d.ts
index f9e377f..ede1e55 100644
--- a/index.d.ts
+++ b/index.d.ts
@@ -63,7 +63,7 @@ interface IDockerComposePushOptions extends IDockerComposeOptions {
 }
 
 interface IDockerComposeResult {
-    exitCode: number;
+    exitCode: ?number;
     out: string;
     err: string;
 }
diff --git a/index.js b/index.js
index 996bd01..c8f1826 100644
--- a/index.js
+++ b/index.js
@@ -67,7 +67,7 @@ const execCompose = (command, args, options) => new Promise((resolve, reject) =>
   });
 
   const result = {
-    exitCode: 0,
+    exitCode: null,
     err: '',
     out: ''
   };