diff --git a/ui/cocoa.m b/ui/cocoa.m
index 1edb944235..5249891651 100644
--- a/ui/cocoa.m
+++ b/ui/cocoa.m
@@ -239,7 +239,7 @@ int keymap[] =
 static int cocoa_keycode_to_qemu(int keycode)
 {
     if (ARRAY_SIZE(keymap) <= keycode) {
-        printf("(cocoa) warning unknown keycode 0x%x\n", keycode);
+        fprintf(stderr, "(cocoa) warning unknown keycode 0x%x\n", keycode);
         return 0;
     }
     return keymap[keycode];