diff --git a/pkg/resmap/factory_test.go b/pkg/resmap/factory_test.go
index 1e13613ed..586955b35 100644
--- a/pkg/resmap/factory_test.go
+++ b/pkg/resmap/factory_test.go
@@ -45,6 +45,11 @@ metadata:
 ---
 # some comment
 ---
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: dply2
+  namespace: test
 ---
 `
 
@@ -68,12 +73,21 @@ metadata:
 					"name": "dply2",
 				},
 			}),
+		resid.NewResIdWithPrefixNamespace(deploy, "dply2", "", "test"): rf.FromMap(
+			map[string]interface{}{
+				"apiVersion": "apps/v1",
+				"kind":       "Deployment",
+				"metadata": map[string]interface{}{
+					"name":      "dply2",
+					"namespace": "test",
+				},
+			}),
 	}
 
 	m, _ := rmF.FromFiles(
 		l, []string{"/home/seans/project/deployment.yaml"})
-	if len(m) != 2 {
-		t.Fatalf("%#v should contain 2 appResource, but got %d", m, len(m))
+	if len(m) != 3 {
+		t.Fatalf("%#v should contain 3 appResource, but got %d", m, len(m))
 	}
 
 	if err := expected.ErrorIfNotEqual(m); err != nil {
diff --git a/pkg/resource/factory_test.go b/pkg/resource/factory_test.go
index 786a6440b..b30a08f6d 100644
--- a/pkg/resource/factory_test.go
+++ b/pkg/resource/factory_test.go
@@ -39,6 +39,7 @@ apiVersion: v1
 kind: ConfigMap
 metadata:
   name: winnie
+  namespace: hundred-acre-wood
 ---
 # some comment
 ---
diff --git a/pkg/resource/resource.go b/pkg/resource/resource.go
index 9bea6f2fc..e952312b8 100644
--- a/pkg/resource/resource.go
+++ b/pkg/resource/resource.go
@@ -58,7 +58,8 @@ func (r *Resource) IsGenerated() bool {
 
 // Id returns the ResId for the resource.
 func (r *Resource) Id() resid.ResId {
-	return resid.NewResId(r.GetGvk(), r.GetName())
+	namespace, _ := r.GetFieldValue("metadata.namespace")
+	return resid.NewResIdWithPrefixNamespace(r.GetGvk(), r.GetName(), "", namespace)
 }
 
 // Merge performs merge with other resource.
diff --git a/pkg/resource/resource_test.go b/pkg/resource/resource_test.go
index cc22bb094..bb4697d92 100644
--- a/pkg/resource/resource_test.go
+++ b/pkg/resource/resource_test.go
@@ -20,6 +20,8 @@ import (
 	"testing"
 
 	"sigs.k8s.io/kustomize/internal/k8sdeps/kunstruct"
+	"sigs.k8s.io/kustomize/pkg/gvk"
+	"sigs.k8s.io/kustomize/pkg/resid"
 )
 
 var factory = NewFactory(
@@ -30,11 +32,12 @@ var testConfigMap = factory.FromMap(
 		"apiVersion": "v1",
 		"kind":       "ConfigMap",
 		"metadata": map[string]interface{}{
-			"name": "winnie",
+			"name":      "winnie",
+			"namespace": "hundred-acre-wood",
 		},
 	})
 
-const testConfigMapString = `unspecified:{"apiVersion":"v1","kind":"ConfigMap","metadata":{"name":"winnie"}}`
+const testConfigMapString = `unspecified:{"apiVersion":"v1","kind":"ConfigMap","metadata":{"name":"winnie","namespace":"hundred-acre-wood"}}`
 
 var testDeployment = factory.FromMap(
 	map[string]interface{}{
@@ -67,3 +70,24 @@ func TestResourceString(t *testing.T) {
 		}
 	}
 }
+
+func TestResourceId(t *testing.T) {
+	tests := []struct {
+		in *Resource
+		id resid.ResId
+	}{
+		{
+			in: testConfigMap,
+			id: resid.NewResIdWithPrefixNamespace(gvk.Gvk{Version: "v1", Kind: "ConfigMap"}, "winnie", "", "hundred-acre-wood"),
+		},
+		{
+			in: testDeployment,
+			id: resid.NewResId(gvk.Gvk{Group: "apps", Version: "v1", Kind: "Deployment"}, "pooh"),
+		},
+	}
+	for _, test := range tests {
+		if test.in.Id() != test.id {
+			t.Fatalf("Expected %v, but got %v\n", test.id, test.in.Id())
+		}
+	}
+}