diff -r c9c877086d8b Lib/logging/config.py
--- a/Lib/logging/config.py	Sun Mar 24 15:21:57 2013 -0700
+++ b/Lib/logging/config.py	Mon Mar 25 14:29:44 2013 +0800
@@ -672,7 +672,8 @@
         else:
             fmt = config.get('format', None)
             dfmt = config.get('datefmt', None)
-            result = logging.Formatter(fmt, dfmt)
+            style = config.get('style', '%')
+            result = logging.Formatter(fmt, dfmt, style)
         return result
 
     def configure_filter(self, config):