diff --git a/plugins/octopress_filters.rb b/plugins/octopress_filters.rb
index 62ee080..1436d4e 100644
--- a/plugins/octopress_filters.rb
+++ b/plugins/octopress_filters.rb
@@ -17,7 +17,7 @@ module Jekyll
   class ContentFilters < PostFilter
     include OctopressFilters
     def pre_render(post)
-      if post.ext.match('html|textile|markdown|haml|slim|xml')
+      if post.ext.match('html|textile|markdown|md|haml|slim|xml')
         post.content = pre_filter(post.content, post.ext)
       end
     end