diff --git a/neutronclient/neutron/v2_0/agentscheduler.py b/neutronclient/neutron/v2_0/agentscheduler.py
index 2d2b1f7d5..4476b1dd3 100644
--- a/neutronclient/neutron/v2_0/agentscheduler.py
+++ b/neutronclient/neutron/v2_0/agentscheduler.py
@@ -219,7 +219,8 @@ class ListL3AgentsHostingRouter(neutronV20.ListCommand):
         # Show the ha_state column only if the server responds with it,
         # as some plugins do not support HA routers.
         if any('ha_state' in agent for agent in data):
-            self.list_columns.append('ha_state')
+            if 'ha_state' not in self.list_columns:
+                self.list_columns.append('ha_state')
         for agent in data:
             agent['alive'] = ":-)" if agent['alive'] else 'xxx'