diff --git a/less/dropdown.less b/less/dropdown.less
index 586a2f4d8..8cb4e25d5 100755
--- a/less/dropdown.less
+++ b/less/dropdown.less
@@ -287,7 +287,7 @@
 }
 
 /* Add fade animation to dropdown menus */
-.open > .dropdown-menu {
+.open:not(.dropup) > .dropdown-menu {
     animation-name: fadeAnimation;
     animation-duration:.7s;
     animation-iteration-count: 1;
@@ -388,4 +388,4 @@
             }
         }
     }
-}
\ No newline at end of file
+}