diff --git a/package.json b/package.json
index ff5c234cd..e0e3c7a4e 100644
--- a/package.json
+++ b/package.json
@@ -36,7 +36,6 @@
     }
   ],
   "dependencies": {
-    "assert": "^1.3.0",
     "react-native-tabs": "^1.0.2"
   },
   "devDependencies": {
diff --git a/src/Actions.js b/src/Actions.js
index 41c9dbb8d..4ba9ba53a 100644
--- a/src/Actions.js
+++ b/src/Actions.js
@@ -6,7 +6,7 @@
  * LICENSE file in the root directory of this source tree.
  *
  */
-import assert from 'assert';
+import { assert } from './Util';
 import Scene from './Scene';
 export const JUMP_ACTION = 'jump';
 export const PUSH_ACTION = 'push';
diff --git a/src/Reducer.js b/src/Reducer.js
index 5ac210ca7..ad8cd0332 100644
--- a/src/Reducer.js
+++ b/src/Reducer.js
@@ -19,7 +19,7 @@ import {
   REFRESH_ACTION,
 } from './Actions';
 
-import assert from 'assert';
+import { assert } from './Util';
 import { getInitialState } from './State';
 
 // WARN: it is not working correct. rewrite it.
diff --git a/src/State.js b/src/State.js
index b8be2a2b2..5ea1bba77 100644
--- a/src/State.js
+++ b/src/State.js
@@ -6,7 +6,7 @@
  * LICENSE file in the root directory of this source tree.
  *
  */
-import assert from 'assert';
+import { assert } from './Util';
 
 function getStateFromScenes(route, scenes, props) {
   const getters = [];
diff --git a/src/Util.js b/src/Util.js
new file mode 100644
index 000000000..03ad54f9c
--- /dev/null
+++ b/src/Util.js
@@ -0,0 +1,5 @@
+export function assert(expr, failDescription) {
+  if (!expr) {
+    throw new Error(`[react-native-router-flux] ${failDescription}`);
+  }
+}