diff --git a/builtin/providers/aws/resource_aws_ecs_service.go b/builtin/providers/aws/resource_aws_ecs_service.go
index aa629829b4..6561674856 100644
--- a/builtin/providers/aws/resource_aws_ecs_service.go
+++ b/builtin/providers/aws/resource_aws_ecs_service.go
@@ -71,6 +71,7 @@ func resourceAwsEcsService() *schema.Resource {
 				Type:     schema.TypeSet,
 				Optional: true,
 				ForceNew: true,
+				MaxItems: 1,
 				Elem: &schema.Resource{
 					Schema: map[string]*schema.Schema{
 						"elb_name": &schema.Schema{