As the main carriers of quality genetic material, stallions are the focal point of equine breeding program, because they are used on a large number of mares and thus have a significant impact on future generations. Breeding stallions are selected based on their pedigree, performance, and conformation. Before entering the breeding program and before each breeding season, each stallion must undergo a breeding soundness examination and be regularly tested for infectious diseases. Breeding soundness examination includes clinical examination, examination of the external genitalia, libido, sexual behavior, and semen evaluation. The plan must be adapted to each stallion individually, since most warmblood stallions are not used solely in breeding but also in sports, and the peak of the sports season coincides with the mating season. Warmblood stallions are often used in breeding and as well in sports usually from the age of three, and their career mostly lasts 15 or more years. Simultaneous use of stallions in breeding and sports is facilitated by various assisted reproduction techniques such as artificial insemination with fresh, cooled, or frozen semen. Each semen collection and handling of semen must be in accordance with biosecurity measures to prevent semen contamination and transmission of infectious diseases. In order to determine a suitable breeding plan for stallion, we should check stallion's ability to produce adequate numbers of morphologically normal sperm that have the ability to remain progressively motile for 24-72 hours when diluted in an acceptable semen extender. Semen should be free of equine arteritis virus, bacteria Taylorella equigenitalis, and other pathogenic bacteria such as Pseudomonas, Klebsiella, and Streptococcus zooepidemicus. The stallion must be constantly under strict health supervision because any deviations from homeostasis can endanger fertility. Also, everything must be in accordance with applicable legislation.