diff --git a/config.def.h b/config.def.h
index 9303208..3382580 100644
--- a/config.def.h
+++ b/config.def.h
@@ -30,7 +30,6 @@ static const Rule rules[] = {
 	 */
 	/* class      instance    title       tags mask     isfloating   monitor */
 	{ "Gimp",     NULL,       NULL,       0,            1,           -1 },
-	{ "Firefox",  NULL,       NULL,       1 << 8,       0,           -1 },
   { "PrismLauncher", NULL,  NULL,       0,            1,           -1 },
   { "imv",      NULL,       NULL,       0,            1,           -1 },
 };