diff --git a/src/lib.rs b/src/lib.rs
index fb2accf73..b0360c540 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -88,7 +88,7 @@
 
 #![doc(html_root_url = "https://docs.rs/tokio-core/0.1")]
 #![deny(missing_docs)]
-//#![deny(warnings)]
+#![deny(warnings)]
 #![warn(missing_debug_implementations)]
 
 extern crate bytes;