diff -r 2bb806539ca6 Doc/library/re.rst
--- a/Doc/library/re.rst	Sat Jun 04 20:53:38 2016 -0700
+++ b/Doc/library/re.rst	Sun Jun 05 00:32:26 2016 -0700
@@ -926,6 +926,17 @@
    The pattern string from which the RE object was compiled.
 
 
+.. attribute:: regex.__pattern_code__
+
+   The compiled code of the regex pattern as a tuple of integers.
+
+   .. impl-detail::
+
+      This attribute is not guaranteed to exist in all implementations of
+      Python. The code returned is an implementation detail that may change
+      without warning between CPython versions.
+
+
 .. _match-objects:
 
 Match Objects
diff -r 2bb806539ca6 Lib/test/test_re.py
--- a/Lib/test/test_re.py	Sat Jun 04 20:53:38 2016 -0700
+++ b/Lib/test/test_re.py	Sun Jun 05 00:32:26 2016 -0700
@@ -587,6 +587,16 @@
             p.groupindex['other'] = 0
         self.assertEqual(p.groupindex['other'], 2)
 
+    @cpython_only
+    def test_code(self):
+        pattern = re.compile('foo')
+        # contents are implementation-defined
+        pattern_code = pattern.__pattern_code__
+        self.assertIsInstance(pattern_code, tuple)
+        for code in pattern_code:
+            self.assertIsInstance(
+                code, int, msg='bad entry in pattern code {}'.format(pattern_code))
+
     def test_special_escapes(self):
         self.assertEqual(re.search(r"\b(b.)\b",
                                    "abcd abc bcd bx").group(1), "bx")
diff -r 2bb806539ca6 Modules/_sre.c
--- a/Modules/_sre.c	Sat Jun 04 20:53:38 2016 -0700
+++ b/Modules/_sre.c	Sun Jun 05 00:32:26 2016 -0700
@@ -1429,13 +1429,36 @@
 
 PyDoc_STRVAR(pattern_doc, "Compiled regular expression objects");
 
-/* PatternObject's 'groupindex' method. */
+/* PatternObject's 'groupindex' attribute. */
 static PyObject *
 pattern_groupindex(PatternObject *self)
 {
     return PyDictProxy_New(self->groupindex);
 }
 
+/* PatternObject's '__pattern_code__' attribute. */
+static PyObject *
+pattern_code(PatternObject *self)
+{
+    PyObject *lst, *entry;
+    const Py_ssize_t codesize = self->codesize;
+    Py_ssize_t i;
+
+    lst = PyTuple_New(self->codesize);
+    if (lst == NULL) {
+        return NULL;
+    }
+    for (i = 0; i < codesize; i++) {
+        entry = PyLong_FromUnsignedLong(self->code[i]);
+        if (entry == NULL) {
+            Py_DECREF(lst);
+            return NULL;
+        }
+        PyTuple_SET_ITEM(lst, i, entry);
+    }
+    return lst;
+}
+
 static int _validate(PatternObject *self); /* Forward */
 
 /*[clinic input]
@@ -2671,6 +2694,8 @@
 static PyGetSetDef pattern_getset[] = {
     {"groupindex", (getter)pattern_groupindex, (setter)NULL,
       "A dictionary mapping group names to group numbers."},
+    {"__pattern_code__", (getter)pattern_code, (setter)NULL,
+      "The pattern's code."},
     {NULL}  /* Sentinel */
 };