diff --git a/src/clj/clojure/core.clj b/src/clj/clojure/core.clj
index 054d350..dde5bce 100644
--- a/src/clj/clojure/core.clj
+++ b/src/clj/clojure/core.clj
@@ -344,7 +344,7 @@
 (defn gensym
   "Returns a new symbol with a unique name. If a prefix string is
   supplied, the name is prefix# where # is some unique number. If
-  prefix is not supplied, the prefix is 'G'."
+  prefix is not supplied, the prefix is 'G__'."
   ([] (gensym "G__"))
   ([prefix-string] (. clojure.lang.Symbol (intern (str prefix-string (str (. clojure.lang.RT (nextID))))))))