diff --git a/devnotes/corelib.org b/devnotes/corelib.org
index 00e57f7a85..b825ee8481 100644
--- a/devnotes/corelib.org
+++ b/devnotes/corelib.org
@@ -517,7 +517,7 @@ as macro
 * test
 * the-ns
 * thread-bound?
-* TODO time
+* DONE time
 * DONE to-array
 * TODO to-array-2d
 * DONE trampoline
diff --git a/src/clj/cljs/core.clj b/src/clj/cljs/core.clj
index ca99f5d7f8..de5225493e 100644
--- a/src/clj/cljs/core.clj
+++ b/src/clj/cljs/core.clj
@@ -635,3 +635,11 @@
   "Creates and installs a new method of multimethod associated with dispatch-value. "
   [multifn dispatch-val & fn-tail]
   `(-add-method ~(with-meta multifn {:tag 'cljs.core.MultiFn}) ~dispatch-val (fn ~@fn-tail)))
+
+(defmacro time
+  "Evaluates expr and prints the time it took. Returns the value of expr."
+  [expr]
+  `(let [start# (.getTime (js/Date.) ())
+         ret# ~expr]
+     (prn (str "Elapsed time: " (- (.getTime (js/Date.) ()) start#) " msecs"))
+     ret#))