diff -r b9a0ecae02cb Lib/copy_reg.py
--- a/Lib/copy_reg.py	Sat Oct 10 10:52:35 2015 +0000
+++ b/Lib/copy_reg.py	Mon Oct 12 23:31:47 2015 +0300
@@ -5,6 +5,7 @@ C, not for instances of user-defined cla
 """
 
 from types import ClassType as _ClassType
+import codecs
 
 __all__ = ["pickle", "constructor",
            "add_extension", "remove_extension", "clear_extension_cache"]
@@ -41,6 +42,17 @@ else:
 
     pickle(complex, pickle_complex, complex)
 
+# Support for pickling Python 3 compatible bytes objects.
+
+try:
+    unicode
+except NameError:
+    Bytes = bytes
+else:
+    class Bytes(bytes):
+        def __reduce__(self):
+            return codecs.encode, (unicode(self, 'latin1'), 'latin1')
+
 # Support for pickling new-style objects
 
 def _reconstructor(cls, base, state):
diff -r b9a0ecae02cb Modules/datetimemodule.c
--- a/Modules/datetimemodule.c	Sat Oct 10 10:52:35 2015 +0000
+++ b/Modules/datetimemodule.c	Mon Oct 12 23:31:47 2015 +0300
@@ -1483,6 +1483,16 @@ static PyObject *us_per_day = NULL;     
 static PyObject *us_per_week = NULL;    /* 1e6*3600*24*7 as Python long */
 static PyObject *seconds_per_day = NULL; /* 3600*24 as Python int */
 
+static PyObject *bytes_class = NULL;
+
+static PyObject *
+convert_bytes(PyObject *bytes)
+{
+    if (bytes != NULL && bytes_class != NULL)
+        bytes = PyObject_CallFunction(bytes_class, "N", bytes);
+    return bytes;
+}
+
 /* ---------------------------------------------------------------------------
  * Class implementations.
  */
@@ -2696,8 +2706,9 @@ date_getstate(PyDateTime_Date *self)
 {
     return Py_BuildValue(
         "(N)",
+        convert_bytes(
         PyString_FromStringAndSize((char *)self->data,
-                                   _PyDateTime_DATE_DATASIZE));
+                                   _PyDateTime_DATE_DATASIZE)));
 }
 
 static PyObject *
@@ -3497,6 +3508,7 @@ time_getstate(PyDateTime_Time *self)
 
     basestate =  PyString_FromStringAndSize((char *)self->data,
                                             _PyDateTime_TIME_DATASIZE);
+    basestate = convert_bytes(basestate);
     if (basestate != NULL) {
         if (! HASTZINFO(self) || self->tzinfo == Py_None)
             result = PyTuple_Pack(1, basestate);
@@ -4570,6 +4582,7 @@ datetime_utctimetuple(PyDateTime_DateTim
  * So it's a tuple in any (non-error) case.
  * __getstate__ isn't exposed.
  */
+
 static PyObject *
 datetime_getstate(PyDateTime_DateTime *self)
 {
@@ -4578,6 +4591,7 @@ datetime_getstate(PyDateTime_DateTime *s
 
     basestate = PyString_FromStringAndSize((char *)self->data,
                                       _PyDateTime_DATETIME_DATASIZE);
+    basestate = convert_bytes(basestate);
     if (basestate != NULL) {
         if (! HASTZINFO(self) || self->tzinfo == Py_None)
             result = PyTuple_Pack(1, basestate);
@@ -4767,6 +4781,7 @@ initdatetime(void)
     PyObject *m;        /* a module object */
     PyObject *d;        /* its dict */
     PyObject *x;
+    PyObject *copyreg;
 
     m = Py_InitModule3("datetime", module_methods,
                        "Fast implementation of the datetime type.");
@@ -4916,6 +4931,14 @@ initdatetime(void)
     us_per_week = PyLong_FromDouble(604800000000.0);
     if (us_per_hour == NULL || us_per_day == NULL || us_per_week == NULL)
         return;
+
+    copyreg = PyImport_ImportModuleNoBlock("copy_reg");
+    if (copyreg == NULL)
+        return;
+    bytes_class = PyObject_GetAttrString(copyreg, "Bytes");
+    Py_DECREF(copyreg);
+    if (bytes_class == NULL)
+        return;
 }
 
 /* ---------------------------------------------------------------------------