diff --git a/src/libcore/str.rs b/src/libcore/str.rs
index b3f58ce2558ff..0e5f956d866f1 100644
--- a/src/libcore/str.rs
+++ b/src/libcore/str.rs
@@ -667,7 +667,7 @@ pure fn eq_slice(a: &str, b: &str) -> bool {
                 unsafe {
                     libc::memcmp(ap as *libc::c_void,
                                  bp as *libc::c_void,
-                                 alen as libc::size_t) == 0
+                                 (alen - 1) as libc::size_t) == 0
                 }
             }
         }
@@ -2225,6 +2225,13 @@ mod tests {
         assert (!eq(&~"foo", &~"bar"));
     }
 
+    #[test]
+    fn test_eq_slice() {
+        assert (eq_slice(view("foobar", 0, 3), "foo"));
+        assert (eq_slice(view("barfoo", 3, 6), "foo"));
+        assert (!eq_slice("foo1", "foo2"));
+    }
+
     #[test]
     fn test_le() {
         assert (le(&"", &""));