diff --git a/repoze/sendmail/encoding.py b/repoze/sendmail/encoding.py
index 03fff54..855e8a4 100644
--- a/repoze/sendmail/encoding.py
+++ b/repoze/sendmail/encoding.py
@@ -71,7 +71,7 @@ def cleanup_message(message,
 
     payload = message.get_payload()
     if payload and isinstance(payload, text_type):
-        charset = message.get_charset()
+        charset = message.get_content_charset()
         if not charset:
             charset, encoded = best_charset(payload)
             message.set_payload(payload, charset=charset)