A horse race is a sporting event in which horses compete against each other around a track, either on the flat or over jumps. The horses may be ridden or driven, and a wide variety of tack is used. The sport is popular throughout the world, and betting on races makes it a profitable enterprise for bookies. Horse racing is often seen as an elite sport, with the best horses and jockeys earning large sums of money. However, a growing body of research suggests that horse racing has negative impacts on the health and wellbeing of horses.

The earliest horse races in Europe were match contests between two, or at most three, horses. Pressure from the public eventually produced events that included larger fields of runners. In addition, rules were developed for selecting the field based on the age, sex, and birthplace of the horses as well as the qualifications of the riders.

Despite these advances, horses continue to die under the exorbitant physical stresses of racing and training. The deaths of Eight Belles and Medina Spirit, both at the Kentucky Derby in 2008, sparked a reassessment of the ethics and integrity of the sport. While racing continues to improve its safety measures, the fact remains that horses routinely suffer catastrophic heart attacks and broken limbs while under the intense physical stress of racing and training.

Horses in a race are typically given medications to help them perform better, and the use of these drugs has been a major focus of the controversy surrounding horse racing. These medicines are administered to horses during training and on race day, primarily for the purpose of preventing pulmonary bleeding, which is common among hard-running thoroughbreds. However, the drugs have many side effects, and they can also harm the environment.

The process of a horse race begins when the horses are brought into the paddock, which is a section of the track where the horses are saddled and ready to be ridden. The jockeys, as they are called, then mount their horses in the paddock and parade them past an official for inspection. Then, they enter the starting gate, which is electrically operated at most tracks. As the race proceeds, stewards and patrol judges look for violations of rules.

At the finish, a judge determines whether the winner has crossed the line first. If the judge does not declare a winner, the next closest horses are declared winners in order of their finishing positions. Spectators can bet on the horse to win, to place, or to show. Winning bets pay out a higher amount than placing or showing bets.

Unlike most other sports, horse races have a long history of legalized gambling. In the United States, horse racing is regulated by the Federal Bureau of Investigation. The sport is also a popular spectator activity, and televised races attract millions of viewers worldwide. In the United Kingdom, horse racing is a national pastime and an important industry.