diff --git a/Lib/httplib.py b/Lib/httplib.py
index 1bca5da..81020b7 100644
--- a/Lib/httplib.py
+++ b/Lib/httplib.py
@@ -813,7 +813,7 @@
                         host_enc = self.host.encode("ascii")
                     except UnicodeEncodeError:
                         host_enc = self.host.encode("idna")
-                    if self.port == HTTP_PORT:
+                    if self.port == self.default_port:
                         self.putheader('Host', host_enc)
                     else:
                         self.putheader('Host', "%s:%s" % (host_enc, self.port))