diff --git a/README.md b/README.md
new file mode 100644
--- /dev/null
+++ b/README.md
@@ -0,0 +1,14 @@
+Data-Timeout
+===========
+
+[![Travis](https://img.shields.io/travis/mvv/data-timeout/master.svg)](https://travis-ci.org/mvv/data-timeout) [![Hackage](https://img.shields.io/hackage/v/data-timeout.svg)](http://hackage.haskell.org/package/data-timeout)
+
+This package provides data types and functions for working with 64-bit
+timeouts of nanosecond precision.
+
+Installation
+------------
+The usual:
+
+	$ cabal install
+
diff --git a/data-timeout.cabal b/data-timeout.cabal
--- a/data-timeout.cabal
+++ b/data-timeout.cabal
@@ -1,5 +1,5 @@
 Name: data-timeout
-Version: 0.3
+Version: 0.3.1
 Category: Data, Concurrency
 Stability: experimental
 Synopsis: 64-bit timeouts of nanosecond precision
@@ -16,6 +16,12 @@
 License: BSD3
 License-File: LICENSE
 
+Extra-Source-Files:
+  README.md
+
+Tested-With: GHC==7.6.3, GHC==7.8.4, GHC==7.10.3, GHC==8.0.2, GHC==8.2.2,
+             GHC==8.4.4, GHC==8.6.1
+
 Cabal-Version: >= 1.6.0
 Build-Type: Simple
 
@@ -24,16 +30,16 @@
   Location: https://github.com/mvv/data-timeout.git
 
 Library
-  Build-Depends:
-    base              >= 4 && < 5,
-    tagged            >= 0.2,
-    text-printer      >= 0.4,
-    data-textual      >= 0.2,
-    parsers           >= 0.5,
-    transformers-base >= 0.3
+  Build-Depends: base              >= 4 && < 5
+               , tagged            >= 0.2
+               , text-printer      >= 0.4
+               , data-textual      >= 0.2
+               , parsers           >= 0.5
+               , transformers-base >= 0.3
+               , stm               >= 2.2
   Hs-Source-Dirs: src
   GHC-Options: -Wall
   Exposed-Modules:
     Data.Timeout
     Control.Concurrent.Timeout
-
+    Control.Concurrent.STM.Timeout
diff --git a/src/Control/Concurrent/STM/Timeout.hs b/src/Control/Concurrent/STM/Timeout.hs
new file mode 100644
--- /dev/null
+++ b/src/Control/Concurrent/STM/Timeout.hs
@@ -0,0 +1,43 @@
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE UnicodeSyntax #-}
+{-# LANGUAGE FlexibleContexts #-}
+
+module Control.Concurrent.STM.Timeout
+  ( registerDelay
+  ) where
+
+import Data.Timeout
+import Control.Monad (void)
+import Control.Monad.Base
+import Control.Monad.STM
+import Control.Concurrent.STM.TVar hiding (registerDelay)
+import GHC.Event (registerTimeout)
+#if MIN_VERSION_base(4,7,0)
+import GHC.Event (getSystemTimerManager)
+#else
+import GHC.Event (getSystemEventManager)
+#endif
+
+registerDelay ∷ MonadBase IO μ ⇒ Timeout → μ (TVar Bool)
+registerDelay tt = liftBase $
+  if tt == instantly
+    then newTVarIO True
+    else do
+      ttv ← newTVarIO False
+#if MIN_VERSION_base(4,7,0)
+      tmm ← getSystemTimerManager
+#else
+      Just tmm ← getSystemEventManager
+#endif
+      let us = tt #> MicroSecond
+          maxUs = fromIntegral (maxBound ∷ Int)
+          us' = maxUs `min` us
+          rearm passed =
+            case us - passed of
+              0 → atomically $ writeTVar ttv True
+              left → do
+                let us'' = maxUs `min` left
+                void $ registerTimeout tmm (fromIntegral us'') $
+                  rearm $ passed + us''
+      void $ registerTimeout tmm (fromIntegral us') $ rearm us'
+      return ttv