diff --git a/servant-client/src/Servant/Common/Req.hs b/servant-client/src/Servant/Common/Req.hs
index b726e7a9..1204181b 100644
--- a/servant-client/src/Servant/Common/Req.hs
+++ b/servant-client/src/Servant/Common/Req.hs
@@ -55,6 +55,8 @@ data ServantError
     }
   deriving (Show)
 
+instance Exception ServantError
+
 data Req = Req
   { reqPath   :: String
   , qs        :: QueryText