A casino, or gambling house, is an establishment where people can gamble. Most casinos offer various kinds of games, such as blackjack, roulette, poker, and craps. Some casinos also have musical shows and other entertainment. Most casinos have security measures to prevent cheating or stealing by patrons.

Casinos generate billions of dollars each year, primarily from gaming revenues. While dazzling theaters, lavish hotels, and other amenities help attract players, casino profits come from the games of chance, such as slot machines, roulette, baccarat, and craps. A small number of casino games involve skill, and players who possess sufficient knowledge can eliminate the inherent long-term advantage of the house (the house edge or vigorish).

Gambling is a popular pastime in many countries, and casinos are widespread throughout the world. The largest concentration of casinos is in the United States, where there are more than 1,000. Most casinos are located in cities such as Las Vegas, Atlantic City, and Chicago. Some are on American Indian reservations and are exempt from state antigambling laws.

Because large amounts of money are handled in a casino, both patrons and staff may be tempted to steal or cheat. Several methods are used to prevent this, including video surveillance, background checks on prospective employees, and random inspections of the property. In addition, the routines and patterns of casino gaming create an environment in which it is easy for security personnel to spot anything out of the ordinary.