diff --git a/README.md b/README.md
index b445bf0..13e57d5 100644
--- a/README.md
+++ b/README.md
@@ -25,6 +25,8 @@ client.set_message_sent_handler(
     lambda pdu: sys.stdout.write('sent {} {}\n'.format(pdu.sequence, pdu.message_id)))
 client.set_message_received_handler(
     lambda pdu: sys.stdout.write('delivered {}\n'.format(pdu.receipted_message_id)))
+client.set_message_alert_handler(
+    lambda pdu: sys.stdout.write('alert {}, is now {} \n'.format(pdu.source_addr, pdu.ms_availability_status)))
 
 client.connect()
 client.bind_transceiver(system_id='login', password='secret')
diff --git a/smpplib/client.py b/smpplib/client.py
index 712f2fa..8924256 100644
--- a/smpplib/client.py
+++ b/smpplib/client.py
@@ -254,6 +254,10 @@ def set_message_sent_handler(self, func):
         """Set new function to handle message sent event"""
         self.message_sent_handler = func
 
+    def set_message_alert_handler(self, func):
+        """Set new function to handle message alert event"""
+        self.message_alert_handler = func
+
     @staticmethod
     def message_received_handler(pdu, **kwargs):
         """Custom handler to process received message. May be overridden"""
@@ -266,6 +270,13 @@ def message_sent_handler(pdu, **kwargs):
         May be overridden"""
         logger.warning('Message sent handler (Override me)')
 
+    @staticmethod
+    def message_alert_handler(pdu, **kwargs):
+        """Called when SMPP server notify us about a MS changed it's state
+        May be overridden"""
+        logger.warning('Message alert handler (Override me)')
+
+
     def listen(self, ignore_error_codes=None):
         """Listen for PDUs and act"""
 
@@ -291,6 +302,8 @@ def listen(self, ignore_error_codes=None):
                     self.message_sent_handler(pdu=p)
                 elif p.command == 'deliver_sm':
                     self._message_received(p)
+                elif p.command == 'alert_notification':
+                    self.message_alert_handler(p)
                 elif p.command == 'enquire_link':
                     self._enquire_link_received()
                 elif p.command == 'enquire_link_resp':
diff --git a/smpplib/command.py b/smpplib/command.py
index ba318ac..4cb224b 100644
--- a/smpplib/command.py
+++ b/smpplib/command.py
@@ -38,6 +38,7 @@ def factory(command_name, **kwargs):
 
     try:
         return {
+            'alert_notification': AlertNotification,
             'bind_transmitter': BindTransmitter,
             'bind_transmitter_resp': BindTransmitterResp,
             'bind_receiver': BindReceiver,
@@ -577,6 +578,42 @@ def __init__(self, command, **kwargs):
         super(GenericNAck, self).__init__(command, need_sequence=False,
             **kwargs)
 
+class AlertNotification(Command):
+    """Notify about a MC which become available and has a delivery pending flag."""
+
+    _defs = []
+
+    params = {
+        'source_addr_ton': Param(type=int, size=1),
+        'source_addr_npi': Param(type=int, size=1),
+        'source_addr': Param(type=str, max=65),
+        'esme_addr_ton': Param(type=int, size=1),
+        'esme_addr_npi': Param(type=int, size=1),
+        'esme_addr': Param(type=str, max=65),
+
+        # Optional params
+        'ms_availability_status': Param(type=int, size=1),
+    }
+
+    params_order = (
+            'source_addr_ton',
+            'source_addr_npi',
+            'source_addr',
+            'esme_addr_ton',
+            'esme_addr_npi',
+            'esme_addr',
+
+            # Optional TLV
+            'ms_availability_status',
+            )
+
+    def __init__(self, command, **kwargs):
+        """Initialize"""
+
+        super(AlertNotification, self).__init__(command, need_sequence=False,
+            **kwargs)
+
+        self._set_vars(**(dict.fromkeys(self.params)))
 
 class SubmitSM(Command):
     """submit_sm command class