diff --git a/serde/src/ser/mod.rs b/serde/src/ser/mod.rs
index 94deb203..cacaa6dd 100644
--- a/serde/src/ser/mod.rs
+++ b/serde/src/ser/mod.rs
@@ -432,5 +432,5 @@ pub fn iterator<I>(iter: I) -> Iterator<I>
     where <I as IntoIterator>::Item: Serialize,
           I: IntoIterator
 {
-    Iterator(RefCell::new(Some(iter.into_iter())))
+    Iterator(RefCell::new(Some(iter)))
 }