diff --git a/Lib/CGIHTTPServer.py b/Lib/CGIHTTPServer.py
index 50e0f7a..2acf913 100644
--- a/Lib/CGIHTTPServer.py
+++ b/Lib/CGIHTTPServer.py
@@ -84,7 +84,7 @@
         path begins with one of the strings in self.cgi_directories
         (and the next character is a '/' or the end of the string).
         """
-        collapsed_path = _url_collapse_path(self.path)
+        collapsed_path = _url_collapse_path(urllib.unquote(self.path))
         dir_sep = collapsed_path.find('/', 1)
         head, tail = collapsed_path[:dir_sep], collapsed_path[dir_sep+1:]
         if head in self.cgi_directories: