diff --git a/pkg/services/ngalert/api/api_prometheus.go b/pkg/services/ngalert/api/api_prometheus.go
index e9781533e4e..002c8071def 100644
--- a/pkg/services/ngalert/api/api_prometheus.go
+++ b/pkg/services/ngalert/api/api_prometheus.go
@@ -144,7 +144,6 @@ func (srv PrometheusSrv) RouteGetRuleStatuses(c *models.ReqContext) response.Res
 					newGroup.LastEvaluation = alertState.LastEvaluationTime
 				}
 
-				alertingRule.Duration = alertState.EvaluationDuration.Seconds()
 				newRule.EvaluationTime = alertState.EvaluationDuration.Seconds()
 
 				switch alertState.State {