diff --git a/src/libstd/hash.rs b/src/libstd/hash.rs
index 2cc7e70747a..55d1411d77e 100644
--- a/src/libstd/hash.rs
+++ b/src/libstd/hash.rs
@@ -61,6 +61,8 @@
  * ```
  */
 
+#![experimental]
+
 pub use core_collections::hash::{Hash, Hasher, Writer, hash, sip};
 
 use default::Default;