diff --git a/src/re_frame/middleware.cljs b/src/re_frame/middleware.cljs
index 0ce0085..8fd2e3e 100644
--- a/src/re_frame/middleware.cljs
+++ b/src/re_frame/middleware.cljs
@@ -22,7 +22,7 @@
   [handler]
   (fn pure-handler
     [app-db event-vec]
-    (if (not (satisfies? IReactiveAtom app-db))
+    (if-not (satisfies? IReactiveAtom app-db)
       (do
         (if (map? app-db)
           (warn "re-frame: Looks like \"pure\" is in the middleware pipeline twice. Ignoring.")