Fry sauce is a regional condiment served with French fries. It is usually a simple combination of one part ketchup and two parts mayonnaise. When spices and other flavorings are added, it is similar to—but thicker and smoother than—traditional Russian dressing and Thousand Island dressing. Fry sauce is commonly found in Utah, much of Idaho, and rural Oregon but relatively unknown elsewhere. Occasionally other ingredients such as barbecue sauce are substituted for ketchup.
The Utah-based Arctic Circle restaurant chain claims to have invented fry sauce around 1949. Arctic Circle serves it in its restaurants in the western United States. Many other fast-food restaurants and family restaurants in the region, such as Burger King, Carl's Jr, Crown Burgers, Apollo Burger and Hires Big H, offer their own versions of the sauce. The condiment is also commonly found in supermarkets in Utah and Idaho, as well as available by mail-order.
Until 1999, Utah franchise locations of McDonald's also carried fry sauce. The chain stopped stocking the condiment because of the high waste it produced: because of its mayonnaise content, the sauce spoils after a single day if left unrefrigerated. Nevertheless, many other national fast food restaurants in Utah and nearby states serve fry sauce.
Among the most popular souvenir pins during the 2002 Winter Olympics in Salt Lake City were ones that depicted fry sauce. Originally sold for US$7.50, these pins became valued at over $60 before the Olympic games started.