The Big Mac, created by Jim Delligatti, debuted nationally at McDonald's in 1968.
Delligatti was a McDonald's franchisee in the Pittsburgh area who developed the sandwich to compete with larger double-decker hamburgers sold by rival restaurants. The final design used two beef patties, a middle bun, lettuce, cheese, pickles, onions, and special sauce.
The Big Mac became one of McDonald's most recognizable branded products and later inspired the “Big Mac Index,” an informal comparison of currency purchasing power published by The Economist. Its name and distinctive construction helped turn a menu item into a major part of McDonald's visual and commercial identity.
The sandwich was tested regionally before its national introduction. The Quarter Pounder is another famous McDonald's burger, but it arrived nationally in 1971 and was not Delligatti's creation.