diff --git a/contrib/mergetools.hgrc b/contrib/mergetools.hgrc
--- a/contrib/mergetools.hgrc
+++ b/contrib/mergetools.hgrc
@@ -13,6 +13,9 @@ gvimdiff.regkey=Software\Vim\GVim
 gvimdiff.regname=path
 gvimdiff.priority=-9
 
+vimdiff.args=$local $other $base
+vimdiff.priority=-10
+
 merge.checkconflicts=True
 merge.priority=-100