Description: Thestudy was conducted to find out the most reliable parameter of the hoof size in relation to the horse body size, exemplified in mares. The mares of four breeds belonging to different origin types were examined: Purebred Arabian, halfbred Anglo-Arabian, primitive Polish Konik and Polish Cold-Blood, 77 mares in total. The mares were four to 13 years old, classified into three age groups. Three body measurements were taken: height at withers, chest circumference and cannon circumference. The boniness index (cannon circumference to height at withers ratio) was also defined. After trimming, three left fore hoof easurements were taken: toe length, solar length and hoof width