diff --git a/hgext/convert/subversion.py b/hgext/convert/subversion.py
--- a/hgext/convert/subversion.py
+++ b/hgext/convert/subversion.py
@@ -197,7 +197,7 @@ def issvnurl(ui, url):
         proto = 'file'
         path = os.path.abspath(url)
     if proto == 'file':
-        path = path.replace(os.sep, '/')
+        path = util.pconvert(path)
     check = protomap.get(proto, lambda *args: False)
     while '/' in path:
         if check(ui, path, proto):