The Filet-O-Fish was created in 1962 as McDonald’s first fish sandwich.
McDonald’s franchisee Lou Groen developed the sandwich for his Cincinnati restaurant, where many customers observed meat-free Catholic dietary practices on Fridays. The original sandwich used a breaded fish fillet, tartar sauce, and cheese on a bun.
The Filet-O-Fish gave McDonald’s a way to serve customers who avoided hamburgers on particular days. It became a permanent menu item and an important example of the company adapting a standardized brand to local customer patterns.
The sandwich is often confused with later chicken products such as the McChicken or Chicken McNuggets. It also predates the Big Mac, which was introduced nationally in 1968. Its fish identity has remained central to its branding.