A "maiden" horse is not a girl. It is a horse that has not yet won a race. Maiden races are designed to find out what new horses can do. Some succeed and go on to higher grades of race. Others, well, they stay "maidens" for a while and then, if they just can't seem to win, they drop out of competition.

Maiden races come in two types: a "claiming race," in which the horse is essentially up for sale, and a "special weight" race, where the horses are not available for purchase. About 30,000 thoroughbred colts and fillies are foaled each year. When they come of age, they can enter competition, but the great majority do not demonstrate much promise for it. If the horse's connections feel the horse is not a potential winner, they may enter him (or her) in a maiden claiming race, where some other owner may "claim" the horse and pay the fee set by race conditions. The price to be paid for claiming a horse out of a Maiden claiming race will range from about half the price of a well-equipped new car up to the price of a small apartment. Obviously, buyers do not appear unless the horse displays some quality that the claimer feels can be successfully developed. Maiden claiming races are the lowest grade of thoroughbred racing. Handicapping is sometimes tricky, as the horse may not have much in the way of performance history, and, as it has never actually won a race, whatever history it does have is not going to be glorious.

If a newcomer shows the owner and trainer that he (or she) has unusual potential, the horse may skip the maiden claiming races and move directly into a grade that is one notch higher. Horses entered in a special weight race can not be claimed by someone else. If that competition proves too steep, the horse may drops back down to the lowest category.

A horse "breaks his maiden" or "graduates" out of the maiden race category by winning one race. When that happens, he will be entered into a higher level of competition. This will be regular claiming races (not maiden claiming races) or allowance races (where claiming does not occur).