diff --git a/Network/Web/Params.hs b/Network/Web/Params.hs
--- a/Network/Web/Params.hs
+++ b/Network/Web/Params.hs
@@ -147,6 +147,7 @@
               | FkCacheControl
               | FkConnection
               | FkContentLength
+              | FkContentRange
               | FkContentType
               | FkCookie
               | FkDate
@@ -169,6 +170,7 @@
                , FkCacheControl
                , FkConnection
                , FkContentLength
+               , FkContentRange
                , FkContentType
                , FkCookie
                , FkDate
@@ -189,6 +191,7 @@
                   , "Cache-Control"
                   , "Connection"
                   , "Content-Length"
+                  , "Content-Range"
                   , "Content-Type"
                   , "Cookie"
                   , "Date"
diff --git a/Network/Web/Server/Basic.hs b/Network/Web/Server/Basic.hs
--- a/Network/Web/Server/Basic.hs
+++ b/Network/Web/Server/Basic.hs
@@ -29,6 +29,8 @@
 import Network.Web.URI
 import System.FilePath
 
+import Text.Printf
+
 ----------------------------------------------------------------
 
 {-|
@@ -165,7 +167,8 @@
           return . Just $ response OK val size ct modified
         Just st@(PartialContent skip len) -> do
           val <- obtain cnf file' $ Just (skip,len)
-          return . Just $ response st val len ct modified
+          let rangeSpec = S.pack $ printf "bytes %d-%d/*" skip (skip+len-1)
+          return . Just $ insertField FkContentRange rangeSpec $ response st val len ct modified
         Just st ->
           return . Just $ response st L.empty 0 ct modified
         _       -> return Nothing -- never reached
diff --git a/webserver.cabal b/webserver.cabal
--- a/webserver.cabal
+++ b/webserver.cabal
@@ -1,5 +1,5 @@
 Name:                   webserver
-Version:                0.5.0.1
+Version:                0.5.1.0
 Author:                 Kazu Yamamoto <kazu@iij.ad.jp>
 Maintainer:             John W. Lato <jwlato@gmail.com>
 License:                BSD3