diff --git a/package.json b/package.json
index 953b7ee..f6909ee 100644
--- a/package.json
+++ b/package.json
@@ -11,7 +11,7 @@
   },
   "devDependencies": {
     "bluebird": "2",
-    "istanbul": "0",
+    "istanbul": "0.4.2",
     "mocha": "2",
     "stream-to-array": "2"
   },