diff --git a/src/libgetopts/lib.rs b/src/libgetopts/lib.rs
index 43b05e7e2e7..5abe96b1acc 100644
--- a/src/libgetopts/lib.rs
+++ b/src/libgetopts/lib.rs
@@ -83,7 +83,7 @@
 #[doc(html_logo_url = "http://www.rust-lang.org/logos/rust-logo-128x128-blk-v2.png",
       html_favicon_url = "http://www.rust-lang.org/favicon.ico",
       html_root_url = "http://static.rust-lang.org/doc/master")];
-#[allow(missing_doc)];
+#[deny(missing_doc)];
 #[allow(deprecated_owned_vector)];
 
 #[feature(globs, phase)];