This article is not about the biological term Warm-blooded.

Warmbloods are a class of horse breeds. They include Hanoverian, Belgian, Holsteiner, Trakehner, Swedish, Dutch, Selle Francais, Oldenburg, and others.

A Warmblood is a breed that combines "hot-blooded" breeds, which are Arabians and Thoroughbreds, with "cold-blooded" breeds, which include many Draft and Pony breeds. The objective of these crosses is to produce a high-quality and attractive riding horse that possesses the calm temperament of the cold-blooded ancestors and the physical performance of the hot-blooded breeds.

Warmblood registries exist for most formally-recognized Warmblood breeds. The goal of these registries is to ensure that the animals that are accepted as breeding stock for the breed stem from acceptable lineage. Registries that are still "open" may permit the infusion of blood from other specified breeds (typically Thoroughbred), often to add more refinement or athletic capability to the still-evolving breed. "Closed" Registries accept only the progeny of two animals that are already included in the Registry.

The American Warmblood Registry has inspections at different farms year round, and horses are judged on their conformation and their pacing. If they pass, they get branded with the American Warmblood Registry symbol on their left haunch.

Most Warmblood registries also include an element of temperament in their inspections. Typically, a Warmblood stallion's progeny cannot be registered into the breed if their sire has not passed very rigorous levels of inspections.

Warmbloods often excel in Dressage and jumping. The hot-blooded breeds still surpass most Warmbloods in endurance sports such as racing, steeplechasing, and endurance riding.

See List of horse breeds