diff --git a/types/express-serve-static-core/index.d.ts b/types/express-serve-static-core/index.d.ts
index dc77fbc4d0..519dbbbb87 100644
--- a/types/express-serve-static-core/index.d.ts
+++ b/types/express-serve-static-core/index.d.ts
@@ -185,7 +185,7 @@ export interface CookieOptions {
     domain?: string;
     secure?: boolean;
     encode?: (val: string) => string;
-    sameSite?: boolean | string;
+    sameSite?: boolean | 'lax' | 'strict' | 'none';
 }
 
 export interface ByteRange { start: number; end: number; }