The aim of this research was to evaluate the polymorphisms of selected genes and to find their potential effect on the occurrence of osteochondrosis in Polish Warmbloods (sport horse breeds). The study was conducted on a group of 198 horses subjected to official performance tests. Investigated joints-fetlock, hock and stifle-were X-rayed twice, once before and again at the end of the tests (first and second examination), and on this basis the degree of disease was evaluated. Based on the results of previous research, 13 candidate genes potentially associated with the occurrence of osteochondrosis were selected and, among them, 32 polymorphisms were tested. Seven SNPs located in the MATN1, CPVL, HYAL1, XIRP2, FRZB, COL5A2 and IGF1 genes were found to be associated with occurrence of osteochondrotic lesions in different joints. These intragenic polymorphisms seem to provide valuable information about the genetic basis of osteochondrosis in sport horse breeds.