encoding can be content-transfer-encoding or content-encoding
diff --git a/Lib/mimetools.py b/Lib/mimetools.py
index 71d0087..06c3828 100644
--- a/Lib/mimetools.py
+++ b/Lib/mimetools.py
@@ -15,7 +15,8 @@
 	def __init__(self, fp, seekable = 1):
 		rfc822.Message.__init__(self, fp, seekable)
 		self.encodingheader = \
-			self.getheader('content-transfer-encoding')
+			self.getheader('content-transfer-encoding') or \
+			self.getheader('content-encoding')
 		self.typeheader = \
 			self.getheader('content-type')
 		self.parsetype()