diff --git a/package.json b/package.json
index 8de8515..8d3a6e3 100644
--- a/package.json
+++ b/package.json
@@ -37,7 +37,7 @@
     "lame": "^1.2.4"
   },
   "devDependencies": {
-    "chai": "^3.5.0",
+    "chai": "^4.0.1",
     "coveralls": "^2.11.14",
     "iced-coffee-coverage": "^1.0.3",
     "iced-coffee-script": "^108.0.11",