diff -r 43ae2a243eca Lib/test/test_ssl.py
--- a/Lib/test/test_ssl.py	Thu Jul 26 00:47:15 2012 +0200
+++ b/Lib/test/test_ssl.py	Fri Jul 27 11:07:41 2012 +1000
@@ -752,6 +752,18 @@
             finally:
                 s.close()
 
+    def test_connect_with_msg_callback(self):
+        with support.transient_internet("svn.python.org"):
+            def cb(packet):
+              self.assertGreater(len(packet), 0)
+            ctx = ssl.SSLContext(ssl.PROTOCOL_SSLv23)
+            ctx.set_msg_callback(cb)
+            s = ctx.wrap_socket(socket.socket(socket.AF_INET))
+            try:
+              s.connect(("svn.python.org", 443))
+            finally:
+                s.close()
+
     def test_connect_capath(self):
         # Verify server certificates using the `capath` argument
         # NOTE: the subject hashing algorithm has been changed between
diff -r 43ae2a243eca Modules/_ssl.c
--- a/Modules/_ssl.c	Thu Jul 26 00:47:15 2012 +0200
+++ b/Modules/_ssl.c	Fri Jul 27 11:07:41 2012 +1000
@@ -181,6 +181,7 @@
     char *npn_protocols;
     int npn_protocols_len;
 #endif
+    PyObject *msg_callback;
 } PySSLContext;
 
 typedef struct {
@@ -1713,6 +1714,7 @@
         return NULL;
     }
     self->ctx = ctx;
+    self->msg_callback = NULL;
     /* Defaults */
     SSL_CTX_set_verify(self->ctx, SSL_VERIFY_NONE, NULL);
     SSL_CTX_set_options(self->ctx,
@@ -1726,6 +1728,55 @@
     return (PyObject *)self;
 }
 
+void
+_msg_callback(int write_p, int version, int content_type, const void *buf,
+              size_t len, SSL *ssl, void *arg)
+{
+    PyObject *args, *result;
+
+#ifdef WITH_THREAD
+    PyGILState_STATE threadstate;
+#endif
+
+    args = Py_BuildValue("(y#)", (char *)buf, len);
+    if(args == NULL)
+        return;
+
+#ifdef WITH_THREAD
+      threadstate = PyGILState_Ensure();
+#endif
+
+    result = PyObject_CallObject(((PySSLContext *)arg)->msg_callback, args);
+    Py_DECREF(args);
+    if (result == NULL)
+        PyErr_Print();
+    Py_DECREF(result);
+
+#ifdef WITH_THREAD
+    PyGILState_Release(threadstate);
+#endif
+}
+
+static PyObject *
+set_msg_callback(PySSLContext *self, PyObject *args)
+{
+    PyObject *temp;
+
+    if (PyArg_ParseTuple(args, "O", &temp)) {
+        if(!PyCallable_Check(temp)) {
+            PyErr_SetString(PyExc_TypeError, "parameter must be callable");
+            return NULL;
+        }
+        Py_XINCREF(temp);
+        if (self->msg_callback)
+            Py_XDECREF(self->msg_callback);
+        self->msg_callback = temp;
+        SSL_CTX_set_msg_callback(self->ctx, _msg_callback);
+        SSL_CTX_set_msg_callback_arg(self->ctx, self);
+    }
+    Py_RETURN_NONE;
+}
+
 static void
 context_dealloc(PySSLContext *self)
 {
@@ -2314,6 +2365,8 @@
                        METH_VARARGS | METH_KEYWORDS, NULL},
     {"set_ciphers", (PyCFunction) set_ciphers,
                     METH_VARARGS, NULL},
+    {"set_msg_callback", (PyCFunction) set_msg_callback,
+                    METH_VARARGS, NULL},
     {"_set_npn_protocols", (PyCFunction) _set_npn_protocols,
                            METH_VARARGS, NULL},
     {"load_cert_chain", (PyCFunction) load_cert_chain,