diff --git a/package.json b/package.json
index d2a1a6e..d71b1fa 100644
--- a/package.json
+++ b/package.json
@@ -20,7 +20,7 @@
   },
   "devDependencies": {
     "mocha": "^2.5.3",
-    "chai": "^3.5.0",
+    "chai": "^4.0.0",
 	"jshint": "^2.9.2",
     "istanbul": "^0.4.3",
     "coveralls": "^2.11.9",