A casino is a place where people play games of chance and gamble. Casinos usually include card rooms, slot machines, and table games like blackjack and roulette. Some casinos also offer sports betting and other forms of gambling. Modern casinos are often combined with hotels, restaurants, and retail shops. They may be operated by a single company or owned by a chain of hotels.

Some casinos are infamous for their links to organized crime. In the past, mafia gangsters controlled many American and European casinos. However, with the rise of real estate and hotel chains and federal crackdowns on mob involvement in gaming, legitimate businesses now run most major casinos. In 2002, the American Gaming Association estimated that 51 million Americans visited casinos—a quarter of all adults over 21.

Casinos are typically designed to appeal to the broadest range of gamblers by offering a variety of games and wagering options. The game selection varies by location; for example, the elegant spa town of Baden-Baden in Germany became famous for its casino when gambling was outlawed in France 150 years ago and still attracts royalty and aristocracy. In the United States most casinos feature a variety of table games and slot machines. Craps attracts big bettors and offers a low house edge; roulette draws small bettors and requires skill; and slots, which are the economic mainstay of most American casinos, pay out winnings at a rate of about 1 percent or less.