diff --git a/Network/Fluent/Logger.hs b/Network/Fluent/Logger.hs
--- a/Network/Fluent/Logger.hs
+++ b/Network/Fluent/Logger.hs
@@ -34,7 +34,6 @@
 import Data.ByteString.Char8 ( unpack )
 import qualified Data.ByteString.Lazy as LBS
 import Data.Monoid ( mconcat )
-import Data.Time ( getCurrentTime, formatTime )
 import qualified Network.Socket as NS
 import Network.Socket.Options ( setRecvTimeout, setSendTimeout )
 import Network.Socket.ByteString.Lazy ( sendAll )
@@ -45,9 +44,9 @@
                               , TChan, newTChanIO, readTChan, peekTChan, writeTChan
                               , TVar, newTVarIO, readTVar, modifyTVar )
 import Control.Exception ( SomeException, handle, bracket, throwIO )
-import System.Locale ( defaultTimeLocale )
 import Data.MessagePack ( Packable, pack )
 import Data.Int ( Int64 )
+import Data.Time.Clock.POSIX ( getPOSIXTime )
 
 -- | Fluent logger settings
 --
@@ -160,8 +159,7 @@
 withFluentLogger set = bracket (newFluentLogger set) closeFluentLogger
 
 getCurrentEpochTime :: IO Int
-getCurrentEpochTime =
-    read . formatTime defaultTimeLocale "%s" <$> getCurrentTime
+getCurrentEpochTime = round <$> getPOSIXTime
 
 -- | Post a message.
 --
diff --git a/fluent-logger.cabal b/fluent-logger.cabal
--- a/fluent-logger.cabal
+++ b/fluent-logger.cabal
@@ -1,5 +1,5 @@
 name:                fluent-logger
-version:             0.1.0.0
+version:             0.1.1.0
 synopsis:            A structured logger for Fluentd (Haskell)
 description:         A structured logger for Fluentd (Haskell) <http://fluentd.org/>
 license:             OtherLicense
@@ -23,8 +23,7 @@
                      , bytestring
                      , network >=2.3.0.13 && <2.5
                      , network-socket-options >=0.1 && <0.3
-                     , time >=1.2.0.3
-                     , old-locale
+                     , time
                      , msgpack >=0.7.1 && <0.8
                      , stm >=2.3
 
@@ -44,7 +43,6 @@
                      , transformers
                      , hspec
                      , attoparsec
-                     , old-locale
                      , time
 
 benchmark fluent-logger-benchmark
diff --git a/test/Network/Fluent/LoggerSpec.hs b/test/Network/Fluent/LoggerSpec.hs
--- a/test/Network/Fluent/LoggerSpec.hs
+++ b/test/Network/Fluent/LoggerSpec.hs
@@ -4,10 +4,9 @@
 import Control.Applicative
 import Control.Concurrent
 import Control.Monad
+import Data.Time.Clock.POSIX ( getPOSIXTime )
 import Data.ByteString ( ByteString )
 import Data.MessagePack
-import Data.Time ( getCurrentTime, formatTime )
-import System.Locale ( defaultTimeLocale )
 import Test.Hspec
 
 import Network.Fluent.Logger
@@ -38,8 +37,7 @@
                           }
 
 getCurrentEpochTime :: IO Int
-getCurrentEpochTime =
-    read . formatTime defaultTimeLocale "%s" <$> getCurrentTime
+getCurrentEpochTime = round <$> getPOSIXTime
 
 postPostsMessage :: IO ()
 postPostsMessage =