diff -r 8b4b8f5d7321 Doc/library/http.client.rst
--- a/Doc/library/http.client.rst	Wed Jun 11 04:36:09 2014 -0700
+++ b/Doc/library/http.client.rst	Wed Jun 11 14:56:30 2014 +0200
@@ -521,8 +521,12 @@
 
    Send data to the server.  This should be used directly only after the
    :meth:`endheaders` method has been called and before :meth:`getresponse` is
-   called.
+   called.  *data* can be a string object, a bytes object, an array object, a
+   file-like object that supports a .read() method, or an iterable object.
 
+   .. versionchanged:: 3.5
+      if a file object is passed and the platform supports it use
+      high-performance :func:`os.sendfile` to transmit the file.
 
 .. _httpresponse-objects:
 
diff -r 8b4b8f5d7321 Lib/http/client.py
--- a/Lib/http/client.py	Wed Jun 11 04:36:09 2014 -0700
+++ b/Lib/http/client.py	Wed Jun 11 14:56:30 2014 +0200
@@ -942,13 +942,15 @@
                     encode = True
                     if self.debuglevel > 0:
                         print("encoding file using iso-8859-1")
-            while 1:
-                datablock = data.read(blocksize)
-                if not datablock:
-                    break
-                if encode:
+            if encode:
+                while 1:
+                    datablock = data.read(blocksize)
+                    if not datablock:
+                        break
                     datablock = datablock.encode("iso-8859-1")
-                self.sock.sendall(datablock)
+                    self.sock.sendall(datablock)
+            else:
+                self.sock.sendfile(data)
             return
         try:
             self.sock.sendall(data)
diff -r 8b4b8f5d7321 Lib/test/test_httplib.py
--- a/Lib/test/test_httplib.py	Wed Jun 11 04:36:09 2014 -0700
+++ b/Lib/test/test_httplib.py	Wed Jun 11 14:56:30 2014 +0200
@@ -55,6 +55,9 @@
         self.sendall_calls += 1
         self.data += data
 
+    def sendfile(self, file):
+        self.data += file.read()
+
     def makefile(self, mode, bufsize=None):
         if mode != 'r' and mode != 'rb':
             raise client.UnimplementedFileMode()