diff --git a/package.json b/package.json
index 2f60879..63dda92 100644
--- a/package.json
+++ b/package.json
@@ -29,7 +29,7 @@
     "babel-core": "^6.8.0",
     "babel-preset-es2015": "^6.6.0",
     "babel-preset-stage-2": "^6.5.0",
-    "chai": "^3.0.0",
+    "chai": "^4.0.1",
     "coveralls": "^2.11.2",
     "errno": "^0.1.2",
     "istanbul": "^0.4.1",