diff --git a/ftplugin/cs.vim b/ftplugin/cs.vim
index 09336d3..7d4c76e 100644
--- a/ftplugin/cs.vim
+++ b/ftplugin/cs.vim
@@ -20,6 +20,7 @@ setlocal formatoptions-=t formatoptions+=croql
 
 " Set 'comments' to format dashed lists in comments.
 setlocal comments=sO:*\ -,mO:*\ \ ,exO:*/,s1:/*,mb:*,ex:*/,:///,://
+setlocal commentstring=//\ %s
 
 setlocal cinoptions=J1