diff --git a/System/Linux/Proc.hs b/System/Linux/Proc.hs
--- a/System/Linux/Proc.hs
+++ b/System/Linux/Proc.hs
@@ -1,4 +1,4 @@
-{-# LANGUAGE TypeOperators, ScopedTypeVariables #-}
+{-# LANGUAGE TypeOperators, ScopedTypeVariables, DeriveDataTypeable #-}
 -- This library is for parse information from /proc on Linux.
 module System.Linux.Proc (
 -- * Types
@@ -19,6 +19,7 @@
 import Data.Int
 import Data.Maybe
 import Data.Word
+import Data.Typeable
 import System.Directory
 import System.FilePath
 import System.Posix.Types
@@ -36,7 +37,7 @@
                   | Zombie
                   | Traced
                   | Paging
-                    deriving (Show, Read, Ord, Eq)
+                    deriving (Show, Read, Ord, Eq, Typeable)
 
 data ProcStatus = 
     ProcStatus {psProcessId      :: Int          -- The process ID.
@@ -45,7 +46,7 @@
                ,psParentProcessId:: Int          -- The PID of the parent
                ,psProcessGroupId :: Int          -- The process group ID of the process
                ,psSessionId      :: Int          -- The session ID of the process
-               } deriving (Show, Read, Ord, Eq)
+               } deriving (Show, Read, Ord, Eq, Typeable)
 
 -- | Path for /proc.
 procPath :: FilePath
diff --git a/proc.cabal b/proc.cabal
--- a/proc.cabal
+++ b/proc.cabal
@@ -1,5 +1,5 @@
 name:			proc
-version:		0.0.3
+version:		0.0.4
 Cabal-Version:	>= 1.8
 license:		GPL-3
 license-file:	LICENSE