diff --git a/Lib/smtpd.py b/Lib/smtpd.py
index e09774f..3992d7b 100755
--- a/Lib/smtpd.py
+++ b/Lib/smtpd.py
@@ -420,7 +420,7 @@
         s = StringIO(data)
         msg = Message.Message(s)
         # These headers are required for the proper execution of Mailman.  All
-        # MTAs in existance seem to add these if the original message doesn't
+        # MTAs in existence seem to add these if the original message doesn't
         # have them.
         if not msg.getheader('from'):
             msg['From'] = mailfrom