diff --git a/types/polymer-ts/index.d.ts b/types/polymer-ts/index.d.ts
index bf7daf936f..7ab10afa47 100644
--- a/types/polymer-ts/index.d.ts
+++ b/types/polymer-ts/index.d.ts
@@ -58,7 +58,7 @@ declare namespace polymer {
         setScrollDirection(direction: string, node: HTMLElement): void;
         shift(path: string, value: any): any;
         splice(path: string, start: number, deleteCount: number, ...items: any[]): any;
-        toggleAttribute(name: string, bool: boolean, node?: HTMLElement): void;
+        toggleAttribute(name: string, force?: boolean, node?: HTMLElement): boolean;
         toggleClass(name: string, bool: boolean, node?: HTMLElement): void;
         transform(transform: string, node?: HTMLElement): void;
         translate3d(x: any, y: any, z: any, node?: HTMLElement): void;