diff --git a/Lib/imaplib.py b/Lib/imaplib.py
index 577b4b9b03a88de..d097a98488e0dac 100644
--- a/Lib/imaplib.py
+++ b/Lib/imaplib.py
@@ -411,8 +411,6 @@ def append(self, mailbox, flags, date_time, message):
         else:
             date_time = None
         literal = MapCRLF.sub(CRLF, message)
-        if self.utf8_enabled:
-            literal = b'UTF8 (' + literal + b')'
         self.literal = literal
         return self._simple_command(name, mailbox, flags, date_time)
 
diff --git a/Lib/test/test_imaplib.py b/Lib/test/test_imaplib.py
index 60f5b671b1da485..8de6ea90250a995 100644
--- a/Lib/test/test_imaplib.py
+++ b/Lib/test/test_imaplib.py
@@ -324,7 +324,7 @@ def cmd_APPEND(self, tag, args):
         typ, data = client.append(None, None, None, msg_string.encode('utf-8'))
         self.assertEqual(typ, 'OK')
         self.assertEqual(server.response,
-            ('UTF8 (%s)\r\n' % msg_string).encode('utf-8'))
+            ('%s\r\n' % msg_string).encode('utf-8'))
 
     def test_search_disallows_charset_in_utf8_mode(self):
         class UTF8Server(SimpleIMAPHandler):
@@ -775,7 +775,7 @@ def cmd_APPEND(self, tag, args):
             self.assertEqual(typ, 'OK')
             self.assertEqual(
                 server.response,
-                ('UTF8 (%s)\r\n' % msg_string).encode('utf-8')
+                ('%s\r\n' % msg_string).encode('utf-8')
             )
 
     # XXX also need a test that makes sure that the Literal and Untagged_status