diff --git a/src/libstd/str.rs b/src/libstd/str.rs
index 5c6895fea43c9..f1a44c4b38639 100644
--- a/src/libstd/str.rs
+++ b/src/libstd/str.rs
@@ -885,7 +885,7 @@ pub mod raw {
     /// If begin is greater than end.
     /// If end is greater than the length of the string.
     #[inline]
-    pub unsafe fn slice_bytes(s: &str, begin: uint, end: uint) -> &str {
+    pub unsafe fn slice_bytes<'a>(s: &'a str, begin: uint, end: uint) -> &'a str {
         do s.as_imm_buf |sbuf, n| {
              assert!((begin <= end));
              assert!((end <= n));