diff --git a/examples/event-sources/resource.yaml b/examples/event-sources/resource.yaml
index c667c24f05..785be862a7 100644
--- a/examples/event-sources/resource.yaml
+++ b/examples/event-sources/resource.yaml
@@ -82,3 +82,14 @@ data:
       labels:
         workflows.argoproj.io/completed: "true"
       prefix: "hello"
+
+  # watch for completed workflows in any namespace
+  example-without-namespace: |-
+    # namespace: (omitted to match any namespace)
+    group: "k8s.io"
+    version: v1
+    kind: Workflow
+    type: ADDED
+    filter:
+      labels:
+        workflows.argoproj.io/completed: "true"
diff --git a/gateways/core/resource/validate.go b/gateways/core/resource/validate.go
index 60a2c59253..4d4947754e 100644
--- a/gateways/core/resource/validate.go
+++ b/gateways/core/resource/validate.go
@@ -37,9 +37,6 @@ func validateResource(config interface{}) error {
 	if res.Version == "" {
 		return fmt.Errorf("resource version must be specified")
 	}
-	if res.Namespace == "" {
-		return fmt.Errorf("resource namespace must be specified")
-	}
 	if res.Kind == "" {
 		return fmt.Errorf("resource kind must be specified")
 	}