diff --git a/internal/controller/install/lookout_controller.go b/internal/controller/install/lookout_controller.go
index 7e20bb0..1b65d16 100644
--- a/internal/controller/install/lookout_controller.go
+++ b/internal/controller/install/lookout_controller.go
@@ -479,7 +479,8 @@ func createLookoutCronJob(lookout *installv1alpha1.Lookout, serviceAccountName s
 			Annotations: map[string]string{"checksum/config": GenerateChecksumConfig(lookout.Spec.ApplicationConfig.Raw)},
 		},
 		Spec: batchv1.CronJobSpec{
-			Schedule: dbPruningSchedule,
+			ConcurrencyPolicy: batchv1.ForbidConcurrent,
+			Schedule:          dbPruningSchedule,
 			JobTemplate: batchv1.JobTemplateSpec{
 				ObjectMeta: metav1.ObjectMeta{
 					Name:      name,
diff --git a/internal/controller/install/lookout_controller_test.go b/internal/controller/install/lookout_controller_test.go
index 96fcfbc..f868cd4 100644
--- a/internal/controller/install/lookout_controller_test.go
+++ b/internal/controller/install/lookout_controller_test.go
@@ -783,6 +783,7 @@ func TestLookoutReconciler_CreateCronJob(t *testing.T) {
 			},
 		},
 		Spec: batchv1.CronJobSpec{
+			ConcurrencyPolicy: batchv1.ForbidConcurrent,
 			JobTemplate: batchv1.JobTemplateSpec{
 				ObjectMeta: metav1.ObjectMeta{
 					Name:      "lookout-db-pruner",
diff --git a/internal/controller/install/scheduler_controller.go b/internal/controller/install/scheduler_controller.go
index d79bc4d..cba6587 100644
--- a/internal/controller/install/scheduler_controller.go
+++ b/internal/controller/install/scheduler_controller.go
@@ -520,7 +520,8 @@ func newSchedulerCronJob(scheduler *installv1alpha1.Scheduler, serviceAccountNam
 			Annotations: map[string]string{"checksum/config": GenerateChecksumConfig(scheduler.Spec.ApplicationConfig.Raw)},
 		},
 		Spec: batchv1.CronJobSpec{
-			Schedule: scheduler.Spec.Pruner.Schedule,
+			Schedule:          scheduler.Spec.Pruner.Schedule,
+			ConcurrencyPolicy: batchv1.ForbidConcurrent,
 			JobTemplate: batchv1.JobTemplateSpec{
 				ObjectMeta: metav1.ObjectMeta{
 					Name:      name,
diff --git a/internal/controller/install/scheduler_controller_test.go b/internal/controller/install/scheduler_controller_test.go
index 58f77fc..c180720 100644
--- a/internal/controller/install/scheduler_controller_test.go
+++ b/internal/controller/install/scheduler_controller_test.go
@@ -969,6 +969,7 @@ func TestSchedulerReconciler_createSchedulerCronJob(t *testing.T) {
 			},
 		},
 		Spec: batchv1.CronJobSpec{
+			ConcurrencyPolicy: batchv1.ForbidConcurrent,
 			JobTemplate: batchv1.JobTemplateSpec{
 				ObjectMeta: metav1.ObjectMeta{
 					Name:      "scheduler-db-pruner",