This investigation was aimed at the study of peculiarities of placentation in Siberian roe (Capreolus capreolus pygargus)--one of the representatives of the Cervidae family which is characterized by an embryonic diapause. Using histological and morphometric methods, the main structural-functional regularities of the organization of roe placenta were determined at different stages of gestation, that included the formation of placenta at later stages of gestation, as compared with other ruminants, prevalence of trophoblastic lining over the connective tissue in terminal villi in the zone of intensive exchange between mother and fetus up to the 5th month of gestation, high degree of capillarity of terminal villi, high numerical density of giant cells in trophoblast. The problems of trophoblast regeneration in the terminal villi and an adaptational role of embryonic diapause in fetal survival and maintenance of vital functions, are discussed.