diff --git a/types/mysql/index.d.ts b/types/mysql/index.d.ts
index ab3f8009ac..7660feb374 100644
--- a/types/mysql/index.d.ts
+++ b/types/mysql/index.d.ts
@@ -100,8 +100,7 @@ interface IPoolCluster {
     add(config: IPoolConfig): void;
     add(group: string, config: IPoolConfig): void;
 
-    end(): void;
-    end(callback: (err: IError, ...args: any[]) => void): void;
+    end(callback?: (err: IError, ...args: any[]) => void): void;
 
     getConnection(callback: (err: IError, connection: IConnection) => void): void;
     getConnection(group: string, callback: (err: IError, connection: IConnection) => void): void;