diff --git a/workflow/util/util.go b/workflow/util/util.go
index eaebd8af8634..dc336ff703b9 100644
--- a/workflow/util/util.go
+++ b/workflow/util/util.go
@@ -1079,7 +1079,14 @@ func patchShutdownStrategy(ctx context.Context, wfClient v1alpha1.WorkflowInterf
 		return errors.InternalWrapError(err)
 	}
 	err = waitutil.Backoff(retry.DefaultRetry, func() (bool, error) {
-		_, err := wfClient.Patch(ctx, name, types.MergePatchType, patch, metav1.PatchOptions{})
+		wf, err := wfClient.Get(ctx, name, metav1.GetOptions{})
+		if err != nil {
+			return !errorsutil.IsTransientErr(err), err
+		}
+		if wf.Status.Fulfilled() {
+			return true, fmt.Errorf("cannot shutdown a completed workflow")
+		}
+		_, err = wfClient.Patch(ctx, name, types.MergePatchType, patch, metav1.PatchOptions{})
 		if apierr.IsConflict(err) {
 			return false, nil
 		}
diff --git a/workflow/util/util_test.go b/workflow/util/util_test.go
index 5ff335f80d74..a6605905beac 100644
--- a/workflow/util/util_test.go
+++ b/workflow/util/util_test.go
@@ -312,6 +312,13 @@ func TestStopWorkflowByNodeName(t *testing.T) {
 	wf, err = wfIf.Get(ctx, "suspend", metav1.GetOptions{})
 	assert.NoError(t, err)
 	assert.Equal(t, wfv1.NodeFailed, wf.Status.Nodes.FindByDisplayName("approve").Phase)
+
+	origWf.Status = wfv1.WorkflowStatus{Phase: wfv1.WorkflowSucceeded}
+	origWf.Name = "succeeded-wf"
+	_, err = wfIf.Create(ctx, origWf, metav1.CreateOptions{})
+	assert.NoError(t, err)
+	err = StopWorkflow(ctx, wfIf, hydratorfake.Noop, "succeeded-wf", "", "")
+	assert.EqualError(t, err, "cannot shutdown a completed workflow")
 }
 
 // Regression test for #6478