diff -r db9fe49069ed Lib/urllib/request.py
--- a/Lib/urllib/request.py	Sun Jul 14 12:45:18 2013 -0700
+++ b/Lib/urllib/request.py	Thu Jul 18 18:15:57 2013 +0800
@@ -1239,7 +1239,12 @@
             h.set_tunnel(req._tunnel_host, headers=tunnel_headers)
 
         try:
-            h.request(req.get_method(), req.selector, req.data, headers)
+            url = req.selector
+            try:
+                url.encode('ascii') 
+            except UnicodeEncodeError:
+                url = quote(req.selector)
+            h.request(req.get_method(), url, req.data, headers)
         except OSError as err: # timeout error
             h.close()
             raise URLError(err)