McDonald's introduced the Big Mac in 1967.
The sandwich was created by Jim Delligatti, a McDonald's franchisee who operated restaurants in the Pittsburgh area. It used two beef patties, a middle bun layer, lettuce, cheese, pickles, onions, and Big Mac sauce, giving the product a distinctive identity within the McDonald's menu.
The Big Mac began as a regional product before becoming a national menu item in the United States. Its name, layered construction, and advertising helped make it one of the most recognizable branded products in fast food.
The Big Mac is sometimes confused with the Big Boy hamburger associated with another restaurant chain. Although both use a middle bun section, the Big Mac is specifically a McDonald's product and was introduced in 1967.