diff --git a/Lib/http/client.py b/Lib/http/client.py
index 8400914..745b999 100644
--- a/Lib/http/client.py
+++ b/Lib/http/client.py
@@ -678,7 +678,10 @@
                 try:
                     port = int(host[i+1:])
                 except ValueError:
-                    raise InvalidURL("nonnumeric port: '%s'" % host[i+1:])
+                    if host[i+1:] == "": # http://foo.com:/ == http://foo.com/
+                        port = self.default_port
+                    else:
+                        raise InvalidURL("nonnumeric port: '%s'" % host[i+1:])
                 host = host[:i]
             else:
                 port = self.default_port