diff --git a/Lib/lib2to3/refactor.py b/Lib/lib2to3/refactor.py
index d2797b9..bd95f3d 100755
--- a/Lib/lib2to3/refactor.py
+++ b/Lib/lib2to3/refactor.py
@@ -177,6 +177,8 @@
         else:
             fixer_pkg = self.fixer_dir
         fixer_pkg = fixer_pkg.replace(os.path.sep, ".")
+        if os.path.altsep:
+            fixer_pkg = self.fixer_dir.replace(os.path.altsep, ".")
         pre_order_fixers = []
         post_order_fixers = []
         fix_names = self.options.fix