diff --git a/streamjs/streamjs-tests.ts b/streamjs/streamjs-tests.ts
index 3d836b56f1..083940311d 100644
--- a/streamjs/streamjs-tests.ts
+++ b/streamjs/streamjs-tests.ts
@@ -12,6 +12,8 @@ Stream.generate(function() {
 });
 Stream.generate(() => 1);
 
+numStream = Stream.iterate(1, (n) => n * 2);
+
 var comparator = (s1, s2) => 0;
 
 numStream = numStream.filter(n => n % 2 == 0);
diff --git a/streamjs/streamjs.d.ts b/streamjs/streamjs.d.ts
index 464a449ca4..3b82680dfd 100644
--- a/streamjs/streamjs.d.ts
+++ b/streamjs/streamjs.d.ts
@@ -9,6 +9,7 @@ declare class Stream<T> {
 	static range (startInclusive: number, endExclusive: number): Stream<number>;
 	static rangeClosed (startInclusive: number, endInclusive: number): Stream<number>;
 	static generate <T> (supplier: Stream.Supplier<T>): Stream<T>;
+	static iterate<T>(seed: T, fn: Stream.Function<T, T>): Stream<T>;
 	// static empty<T>(): Stream<T>;
 	
 	anyMatch(predicate: Stream.Predicate<T>): boolean;