diff --git a/package.json b/package.json
index 91f97aa..a839bf0 100644
--- a/package.json
+++ b/package.json
@@ -16,7 +16,7 @@
     "grunt": "0.4.5",
     "grunt-cafe-mocha": "0.1.13",
     "grunt-cli": "0.1.13",
-    "chai": "3.3.0",
+    "chai": "4.0.1",
     "mocha": "1.9.0",
     "grunt-contrib-watch": "0.3.1",
     "grunt-peg": "1.4.0",