The Big Mac, introduced nationally by McDonald's in 1968, became one of the company's most important branded products.
Franchisee Jim Delligatti created the sandwich in the Pittsburgh area after developing a larger burger for customers who wanted a more substantial meal. It used two beef patties, a middle bun section, lettuce, cheese, pickles, onions, and special sauce.
The Big Mac was distinctive enough to receive its own name and advertising identity rather than functioning as an unnamed menu variation. Its layered construction also helped make the sandwich a visual shorthand for McDonald's around the world.
The sandwich is often associated with the Big Mac Index, an informal economic comparison created by The Economist in 1986. That index uses the sandwich's prices to discuss purchasing-power differences between currencies.