diff --git a/src/cljs/cljs/core.cljs b/src/cljs/cljs/core.cljs
index 3fc2455de2..722c4a11c8 100644
--- a/src/cljs/cljs/core.cljs
+++ b/src/cljs/cljs/core.cljs
@@ -452,7 +452,7 @@
   (-equiv [x o] (identical? x o))
 
   IHash
-  (-hash [o] o))
+  (-hash [o] (js-mod (.floor js/Math o) 2147483647)))
 
 (extend-type boolean
   IHash
diff --git a/test/cljs/cljs/core_test.cljs b/test/cljs/cljs/core_test.cljs
index 253e80ea24..d33abcbdb8 100644
--- a/test/cljs/cljs/core_test.cljs
+++ b/test/cljs/cljs/core_test.cljs
@@ -1778,5 +1778,10 @@
   (assert (instance? js/Error (ex-info "asdf" {:foo 1})))
   (assert (not (instance? cljs.core.ExceptionInfo (js/Error.))))
 
+  ;; CLJS-435
+
+  (assert (= (assoc {} 154618822656 1 261993005056 1)
+             {154618822656 1 261993005056 1}))
+
   :ok
   )