diff --git a/HTTP.cabal b/HTTP.cabal
--- a/HTTP.cabal
+++ b/HTTP.cabal
@@ -1,5 +1,5 @@
 Name: HTTP
-Version: 4000.3.7
+Version: 4000.3.8
 Cabal-Version: >= 1.8
 Build-type: Simple
 License: BSD3
diff --git a/Network/HTTP/Proxy.hs b/Network/HTTP/Proxy.hs
--- a/Network/HTTP/Proxy.hs
+++ b/Network/HTTP/Proxy.hs
@@ -160,6 +160,7 @@
 -- | @parseProxy str@ translates a proxy server string into a @Proxy@ value;
 -- returns @Nothing@ if not well-formed.
 parseProxy :: String -> Maybe Proxy
+parseProxy "" = Nothing
 parseProxy str = join
                    . fmap uri2proxy
                    $ parseHttpURI str