diff --git a/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/impl_idl_ovn.py b/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/impl_idl_ovn.py
index 822a3b7d6dc..c8a5c9ae53a 100644
--- a/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/impl_idl_ovn.py
+++ b/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/impl_idl_ovn.py
@@ -817,8 +817,7 @@ class OvsdbSbOvnIdl(sb_impl_idl.OvnSbApiIdlImpl, Backend):
 
     def _get_chassis_physnets(self, chassis):
         bridge_mappings = chassis.external_ids.get('ovn-bridge-mappings', '')
-        mapping_dict = helpers.parse_mappings(bridge_mappings.split(','),
-                                              unique_values=False)
+        mapping_dict = helpers.parse_mappings(bridge_mappings.split(','))
         return list(mapping_dict.keys())
 
     def chassis_exists(self, hostname):
diff --git a/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovsdb_monitor.py b/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovsdb_monitor.py
index b140022e8f8..8a834626474 100644
--- a/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovsdb_monitor.py
+++ b/neutron/plugins/ml2/drivers/ovn/mech_driver/ovsdb/ovsdb_monitor.py
@@ -137,8 +137,7 @@ class ChassisEvent(row_event.RowEvent):
         phy_nets = []
         if event != self.ROW_DELETE:
             bridge_mappings = row.external_ids.get('ovn-bridge-mappings', '')
-            mapping_dict = helpers.parse_mappings(bridge_mappings.split(','),
-                                                  unique_values=False)
+            mapping_dict = helpers.parse_mappings(bridge_mappings.split(','))
             phy_nets = list(mapping_dict)
 
         self.driver.update_segment_host_mapping(host, phy_nets)
diff --git a/neutron/tests/functional/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_impl_idl.py b/neutron/tests/functional/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_impl_idl.py
index 18b35232ede..ce45aa23126 100644
--- a/neutron/tests/functional/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_impl_idl.py
+++ b/neutron/tests/functional/plugins/ml2/drivers/ovn/mech_driver/ovsdb/test_impl_idl.py
@@ -53,7 +53,7 @@ class TestSbApi(BaseOvnIdlTest):
                 {'external_ids': {'ovn-bridge-mappings':
                                   'public:br-ex,private:br-0'}},
                 {'external_ids': {'ovn-bridge-mappings':
-                                  'public:br-ex,public2:br-ex'}},
+                                  'public:br-ex,public2:br-ex2'}},
                 {'external_ids': {'ovn-bridge-mappings':
                                   'public:br-ex'}},
             ]
@@ -99,6 +99,15 @@ class TestSbApi(BaseOvnIdlTest):
         self.assertGreaterEqual(set(mapping.keys()),
                                 {c['name'] for c in self.data['chassis']})
 
+    def test_multiple_physnets_in_one_bridge(self):
+        self.data = {
+            'chassis': [
+                {'external_ids': {'ovn-bridge-mappings': 'p1:br-ex,p2:br-ex'}}
+            ]
+        }
+        self.load_test_data()
+        self.assertRaises(ValueError, self.api.get_chassis_and_physnets)
+
     def _add_switch_port(self, chassis_name, type='localport'):
         sname, pname = (utils.get_rand_device_name(prefix=p)
                         for p in ('switch', 'port'))
diff --git a/releasenotes/notes/ovn-limit-one-physnet-per-bridge-188285955a5ea124.yaml b/releasenotes/notes/ovn-limit-one-physnet-per-bridge-188285955a5ea124.yaml
new file mode 100644
index 00000000000..fcb0ca76204
--- /dev/null
+++ b/releasenotes/notes/ovn-limit-one-physnet-per-bridge-188285955a5ea124.yaml
@@ -0,0 +1,4 @@
+---
+other:
+  - |
+    OVN mechanism driver allows only to have one physical network per bridge.