diff --git a/Lib/urllib/request.py b/Lib/urllib/request.py
--- a/Lib/urllib/request.py
+++ b/Lib/urllib/request.py
@@ -92,11 +92,14 @@
 import re
 import socket
 import sys
+import stat
 import time
 import collections
 import tempfile
 import contextlib
+import mimetypes
 import warnings
+import threading
 
 
 from urllib.error import URLError, HTTPError, ContentTooShortError
@@ -701,6 +704,106 @@
               "lead to an infinite loop.\n" \
               "The last 30x error message was:\n"
 
+# Utility function for MultipartPostHandler
+
+_counter_lock = threading._allocate_lock()
+
+_counter = 0
+def _get_next_counter():
+    global _counter
+    _counter_lock.acquire()
+    _counter += 1
+    result = _counter
+    _counter_lock.release()
+    return result
+
+_prefix = None
+
+def _choose_boundary():
+    """Return a string usable as a multipart boundary.
+
+    The string chosen is unique within a single program run, and
+    incorporates the user id (if available), process id (if available),
+    and current time.  So it's very unlikely the returned string appears
+    in message text, but there's no guarantee.
+
+    The boundary contains dots so you have to quote it in the header."""
+
+    global _prefix
+    if _prefix is None:
+        import socket
+        try:
+            hostid = socket.gethostbyname(socket.gethostname())
+        except socket.gaierror:
+            hostid = '127.0.0.1'
+        try:
+            uid = repr(os.getuid())
+        except AttributeError:
+            uid = '1'
+        try:
+            pid = repr(os.getpid())
+        except AttributeError:
+            pid = '1'
+        _prefix = hostid + '.' + uid + '.' + pid
+    return "%s.%.3f.%d" % (_prefix, time.time(), _get_next_counter())
+
+
+class MultipartPostHandler(BaseHandler):
+
+    handler_order = 480
+
+    def _multipart_encode(self, parts, files, boundary = None, buf=None):
+        if boundary is None:
+            boundary = _choose_boundary()
+        if buf is None:
+            buf = ''
+        for (key, value) in parts:
+            buf += '--%s\r\n' % boundary
+            buf += 'Content-Disposition: form-data; name="%s"' % key
+            buf += '\r\n\r\n' + value + '\r\n'
+        for (key, fd) in files:
+            file_size = os.fstat(fd.fileno())[stat.ST_SIZE]
+            filename = fd.name.split('/')[-1]
+            contenttype = mimetypes.guess_type(filename)[0] or 'application/octet-stream'
+            buf += '--%s\r\n' % boundary
+            buf += 'Content-Disposition: form-data; name="%s"; filename="%s"\r\n' % (key, filename)
+            buf += 'Content-Type: %s\r\n' % contenttype
+            fd.seek(0)
+            buf += '\r\n' + fd.read() + '\r\n'
+        buf += '--%s--\r\n\r\n' % boundary
+
+        return boundary, buf
+
+    def http_request(self, request):
+        data = request.get_data()
+        if data is not None and type(data) != str:
+            v_files = []
+            v_vars = []
+            try:
+                for (key, value) in data.items():
+                    if type(value) == file:
+                        v_files.append((key, value))
+                    else:
+                        v_vars.append((key, value))
+            except TypeError:
+                systype, value, traceback = sys.exc_info()
+                raise TypeError("Not a Valid non-string sequence"
+                        " or a mapping object")
+            if len(v_files) == 0:
+                data = urllib.parse.urlencode(v_vars, doseq)
+            else:
+                boundary, data = self._multipart_encode(v_vars, v_files)
+                contenttype = 'multipart/form-data: boundary=%s' % boundary
+                if (request.has_header('Content-Type') and\
+                    request.get_header('Content-Type').find('multipart/form-data') != 0):
+                    # Setting Content-Type to multipart/form-data
+                    request.add_unredirected_header('Content-Type', contenttype)
+
+            request.add_data(data)
+        return request
+
+    https_request = http_request
+
 
 def _parse_proxy(proxy):
     """Return (scheme, user, password, host/port) given a URL or an authority.