The study was conducted on 22 Thoroughbred mares and their progeny for four foaling seasons. Blood from the mares was sampled in 36th-48th h after delivery. Blood of the foals was sampled in the course of delivery and in 3rd -4th week of life. Results indicate that serum vitamin D-binding protein (DBP) concentration did not differ in the mares and in their newborns and 3-4-week- old foals, whose DBP had F, and FS phenotypes. It was concluded that phenotype of DBP is not related with serum DBP concentration.