Index: Modules/_multiprocessing/pipe_connection.c
===================================================================
--- Modules/_multiprocessing/pipe_connection.c	(revision 70789)
+++ Modules/_multiprocessing/pipe_connection.c	(working copy)
@@ -17,11 +17,28 @@
 static Py_ssize_t
 conn_send_string(ConnectionObject *conn, char *string, size_t length)
 {
+	BOOL ret = TRUE;
 	DWORD amount_written;
-	BOOL ret;
+	Py_ssize_t offset = 0;
 
 	Py_BEGIN_ALLOW_THREADS
-	ret = WriteFile(conn->handle, string, length, &amount_written, NULL);
+	if (length == 0)
+		ret = WriteFile(conn->handle, string, 0, &amount_written, NULL);
+	else {
+		while (ret && offset < length) {
+			DWORD len_to_write = MIN(length - offset, 32 * 1024);
+
+			ret = WriteFile(conn->handle, string + offset, len_to_write, &amount_written, NULL);
+			offset += amount_written;
+
+			if (offset < length) {
+				// ERROR_NO_SYSTEM_RESOURCES occurs when OS internal buffer is full
+				// and can't be sent to other process immediately
+				if (ret == 0 && GetLastError() == ERROR_NO_SYSTEM_RESOURCES)
+					ret = TRUE;
+			}
+		}
+	}
 	Py_END_ALLOW_THREADS
 	return ret ? MP_SUCCESS : MP_STANDARD_ERROR;
 }
Index: Lib/test/test_multiprocessing.py
===================================================================
--- Lib/test/test_multiprocessing.py	(revision 70789)
+++ Lib/test/test_multiprocessing.py	(working copy)
@@ -1228,6 +1228,19 @@
 
     ALLOWED_TYPES = ('processes', 'threads')
 
+    
+    def _read_until_sentinel(self, conn):
+        recv_list = []
+        for msg in iter(conn.recv_bytes, SENTINEL):
+            recv_list.append(msg)
+        return latin('').join(recv_list)
+        
+    def _echo_large(self, conn):
+        msg = self._read_until_sentinel(conn)
+        conn.send_bytes(msg)
+        conn.send_bytes(SENTINEL)
+        conn.close()
+        
     def _echo(self, conn):
         for msg in iter(conn.recv_bytes, SENTINEL):
             conn.send_bytes(msg)
@@ -1291,15 +1304,11 @@
         self.assertEqual(poll(TIMEOUT1), True)
         self.assertTimingAlmostEqual(poll.elapsed, 0)
 
+        conn.send_bytes(SENTINEL)                          # tell child to quit
         self.assertEqual(conn.recv(), None)
 
-        really_big_msg = latin('X') * (1024 * 1024 * 16)   # 16Mb
-        conn.send_bytes(really_big_msg)
-        self.assertEqual(conn.recv_bytes(), really_big_msg)
-
-        conn.send_bytes(SENTINEL)                          # tell child to quit
         child_conn.close()
-
+        
         if self.TYPE == 'processes':
             self.assertEqual(conn.readable, True)
             self.assertEqual(conn.writable, True)
@@ -1307,7 +1316,26 @@
             self.assertRaises(EOFError, conn.recv_bytes)
 
         p.join()
+        
+    def test_large_msg(self):
+        
+        conn, child_conn = self.Pipe()
 
+        p = self.Process(target=self._echo_large, args=(child_conn,))
+        p.daemon = True
+        p.start()
+
+        really_big_msg = latin('X') * (1024 * 1024) # * 16)   # 128Mb
+        conn.send_bytes(really_big_msg)
+        conn.send_bytes(SENTINEL)                          # tell child to quit
+        rcvd = self._read_until_sentinel(conn)
+        self.assertEqual(rcvd, really_big_msg)
+
+        child_conn.close()
+
+        p.join()
+        
+
     def test_duplex_false(self):
         reader, writer = self.Pipe(duplex=False)
         self.assertEqual(writer.send(1), None)