The competitive horse racing is one of humankind's earlier sports, having its origins at the prehistoric nomadic tribesmen of Central Asia who first domesticated the horse about 4500 BC. For thousands of years, horse racing increased as the sport of kings and the aristocracy. Recent racings, however, exists primarily because it is a major way for legalized gambling.

Horse racing is the second most typically attended U.S. sport fans, after baseball. In 1989, 56,194,565 people attended 8,004 days of racing, gambling $9.14 billion. Horse racing is also a major professional sport in Canada, Great Britain, Ireland, Western Europe, Australia, New Zealand, South Africa, and South America.

By far the most popular type of sport is the racing of mounted thoroughbred horses over flat courses at distances from three-quarters of a mile to two miles. Other major forms of horse racing are harness racing, steeplechase racing, and quarter horse racing.