diff --git a/neutron/callbacks/resources.py b/neutron/callbacks/resources.py
index 410809dc9c7..028cc715376 100644
--- a/neutron/callbacks/resources.py
+++ b/neutron/callbacks/resources.py
@@ -24,6 +24,7 @@ ROUTER_GATEWAY = 'router_gateway'
 ROUTER_INTERFACE = 'router_interface'
 SECURITY_GROUP = 'security_group'
 SECURITY_GROUP_RULE = 'security_group_rule'
+SEGMENT = 'segment'
 SUBNET = 'subnet'
 SUBNETS = 'subnets'
 SUBNET_GATEWAY = 'subnet_gateway'
diff --git a/neutron/services/segments/db.py b/neutron/services/segments/db.py
index a6dae924487..2ac39e1eb7d 100644
--- a/neutron/services/segments/db.py
+++ b/neutron/services/segments/db.py
@@ -33,6 +33,7 @@ from neutron.db import common_db_mixin
 from neutron.db import model_base
 from neutron.db import segments_db as db
 from neutron.extensions import segment as extension
+from neutron import manager
 from neutron.services.segments import exceptions
 
 
@@ -110,6 +111,8 @@ class SegmentDbMixin(common_db_mixin.CommonDbMixin):
                     db.SEGMENTATION_ID: segmentation_id}
             new_segment = db.NetworkSegment(**args)
             context.session.add(new_segment)
+            registry.notify(resources.SEGMENT, events.PRECOMMIT_CREATE, self,
+                            context=context, segment=new_segment)
 
         return self._make_segment_dict(new_segment)
 
@@ -221,6 +224,24 @@ def _update_segment_host_mapping_for_agent(resource, event, trigger,
     update_segment_host_mapping(context, host, current_segment_ids)
 
 
+def _add_segment_host_mapping_for_segment(resource, event, trigger,
+                                          context, segment):
+    if not segment.physical_network:
+        return
+    cp = manager.NeutronManager.get_plugin()
+    check_segment_for_agent = getattr(cp, 'check_segment_for_agent', None)
+    if not hasattr(cp, 'get_agents') or not check_segment_for_agent:
+        # not an agent-supporting plugin
+        registry.unsubscribe(_add_segment_host_mapping_for_segment,
+                             resources.SEGMENT, events.PRECOMMIT_CREATE)
+        return
+    hosts = {agent['host'] for agent in cp.get_agents(context)
+             if check_segment_for_agent(segment, agent)}
+    for host in hosts:
+        context.session.add(SegmentHostMapping(segment_id=segment.id,
+                                               host=host))
+
+
 def subscribe():
     registry.subscribe(_update_segment_host_mapping_for_agent,
                        resources.AGENT,
@@ -228,5 +249,7 @@ def subscribe():
     registry.subscribe(_update_segment_host_mapping_for_agent,
                        resources.AGENT,
                        events.AFTER_UPDATE)
+    registry.subscribe(_add_segment_host_mapping_for_segment,
+                       resources.SEGMENT, events.PRECOMMIT_CREATE)
 
 subscribe()
diff --git a/neutron/tests/unit/extensions/test_segment.py b/neutron/tests/unit/extensions/test_segment.py
index a150a89cb1f..113e673d7b9 100644
--- a/neutron/tests/unit/extensions/test_segment.py
+++ b/neutron/tests/unit/extensions/test_segment.py
@@ -392,6 +392,19 @@ class TestMl2HostSegmentMappingOVS(HostSegmentMappingTestCase):
                          segments_host_db[segment['id']]['segment_id'])
         self.assertEqual(host2, segments_host_db[segment['id']]['host'])
 
+    def test_new_segment_after_host_reg(self):
+        host1 = 'host1'
+        physical_network = 'phys_net1'
+        segment = self._test_one_segment_one_host(host1)
+        with self.network() as network:
+            network = network['network']
+        segment2 = self._test_create_segment(
+            network_id=network['id'], physical_network=physical_network,
+            segmentation_id=200, network_type=p_constants.TYPE_VLAN)['segment']
+        segments_host_db = self._get_segments_for_host(host1)
+        self.assertEqual(set((segment['id'], segment2['id'])),
+                         set(segments_host_db))
+
     def test_segment_deletion_removes_host_mapping(self):
         host = 'host1'
         segment = self._test_one_segment_one_host(host)