diff --git a/src/packages/gfm/grammars/gfm.cson b/src/packages/gfm/grammars/gfm.cson
index d8c5d2826..0a419f40f 100644
--- a/src/packages/gfm/grammars/gfm.cson
+++ b/src/packages/gfm/grammars/gfm.cson
@@ -3,6 +3,7 @@
 'fileTypes': [
   'markdown'
   'md'
+  'mdown'
   'mkd'
   'mkdown'
   'ron'