diff --git a/src/libtime/lib.rs b/src/libtime/lib.rs
index 9ac1e2a615715..56a22bb2addeb 100644
--- a/src/libtime/lib.rs
+++ b/src/libtime/lib.rs
@@ -203,7 +203,7 @@ pub fn tzset() {
 
 /// Holds a calendar date and time broken down into its components (year, month, day, and so on),
 /// also called a broken-down time value.
-#[deriving(Clone, PartialEq, Show)]
+#[deriving(Clone, PartialEq, Eq, Show)]
 pub struct Tm {
     /// Seconds after the minute - [0, 60]
     pub tm_sec: i32,