diff --git a/core/src/main/scala/spark/RDD.scala b/core/src/main/scala/spark/RDD.scala
index 590106388a..505ef76941 100644
--- a/core/src/main/scala/spark/RDD.scala
+++ b/core/src/main/scala/spark/RDD.scala
@@ -163,7 +163,7 @@ class FlatMappedRDD[U: ClassManifest, T: ClassManifest](
 extends RDD[U](prev.context) {
   override def splits = prev.splits
   override val dependencies = List(new OneToOneDependency(prev))
-  override def compute(split: Split) = prev.iterator(split).toStream.flatMap(f).iterator
+  override def compute(split: Split) = prev.iterator(split).flatMap(f)
 }
 
 class FilteredRDD[T: ClassManifest](
@@ -314,8 +314,8 @@ extends RDD[(K, U)](prev.context) {
   override val dependencies = List(new OneToOneDependency(prev))
   override val partitioner = prev.partitioner
   override def compute(split: Split) = {
-    prev.iterator(split).toStream.flatMap { 
+    prev.iterator(split).flatMap {
       case (k, v) => f(v).map(x => (k, x))
-    }.iterator
+    }
   }
 }