diff --git a/Web/Authenticate/OAuth.hs b/Web/Authenticate/OAuth.hs
--- a/Web/Authenticate/OAuth.hs
+++ b/Web/Authenticate/OAuth.hs
@@ -223,7 +223,7 @@
   bsBodyQ <- if isBodyFormEncoded $ requestHeaders req
                   then liftM parseSimpleQuery $ toLBS (requestBody req)
                   else return []
-  let bsAuthParams = filter ((`elem`["oauth_consumer_key","oauth_token", "oauth_version","oauth_signature_method","oauth_timestamp", "oauth_nonce", "oauth_verifier", "oauth_version"]).fst) $ unCredential tok
+  let bsAuthParams = filter ((`elem`["oauth_consumer_key","oauth_token", "oauth_version","oauth_signature_method","oauth_timestamp", "oauth_nonce", "oauth_verifier", "oauth_version","oauth_callback"]).fst) $ unCredential tok
       allParams = bsQuery++bsBodyQ++bsAuthParams
       bsParams = BS.intercalate "&" $ map (\(a,b)->BS.concat[a,"=",b]) $ sortBy compareTuple
                    $ map (\(a,b) -> (paramEncode a,paramEncode b)) allParams
diff --git a/authenticate.cabal b/authenticate.cabal
--- a/authenticate.cabal
+++ b/authenticate.cabal
@@ -1,8 +1,8 @@
 name:            authenticate
-version:         0.9.1.5
+version:         0.9.1.6
 license:         BSD3
 license-file:    LICENSE
-author:          Michael Snoyman <michael@snoyman.com>
+author:          Michael Snoyman, Hiromi Ishii
 maintainer:      Michael Snoyman <michael@snoyman.com>
 synopsis:        Authentication methods for Haskell web applications.
 description:     Focus is on third-party authentication methods, such as OpenID,