diff --git a/Lib/email/encoders.py b/Lib/email/encoders.py
index 06016cd..c1a44aa 100644
--- a/Lib/email/encoders.py
+++ b/Lib/email/encoders.py
@@ -75,7 +75,7 @@
         # iso-2022-* is non-ASCII but still 7-bit
         charset = msg.get_charset()
         output_cset = charset and charset.output_charset
-        if output_cset and output_cset.lower().startswith('iso-2202-'):
+        if output_cset and output_cset.lower().startswith('iso-2022-'):
             msg['Content-Transfer-Encoding'] = '7bit'
         else:
             msg['Content-Transfer-Encoding'] = '8bit'