Index: Lib/xml/etree/ElementTree.py
===================================================================
--- Lib/xml/etree/ElementTree.py	(revision 73267)
+++ Lib/xml/etree/ElementTree.py	(working copy)
@@ -742,7 +742,7 @@
 
 def _encode(s, encoding):
     if encoding:
-        return s.encode(encoding)
+        return s.encode(encoding, 'xmlcharrefreplace')
     else:
         return s