diff --git a/lib/chai-as-promised.js b/lib/chai-as-promised.js
index 4ffdb2e..ee984b9 100644
--- a/lib/chai-as-promised.js
+++ b/lib/chai-as-promised.js
@@ -1,8 +1,12 @@
 import * as checkErrorDefault from 'check-error';
 
+let alreadySetUp = false;
 let checkError = checkErrorDefault;
 
 export default function (chai, utils) {
+  if (alreadySetUp) return;
+  alreadySetUp = true;
+
   const Assertion = chai.Assertion;
   const assert = chai.assert;
   const proxify = utils.proxify;