Index: genshi/_speedups.c
===================================================================
--- genshi/_speedups.c	(revision 796)
+++ genshi/_speedups.c	(working copy)
@@ -417,6 +417,7 @@
     }
     PyTuple_SET_ITEM(args, 0, result);
     result = PyString_Format(format, args);
+    Py_DECREF(format);
     Py_DECREF(args);
     return result;
 }