Morphometric, cytometric and immunohistochemically methods have been used to research the effect of chronic toxic hepatitis (CTH) of the mother on the formation of the offspring spleen in the dynamics of early postnatal ontogenesis. We used 120 female outbred rats weighing 110-120 g, and 120 male rat pups on days 1, 3, 7, 15, 21 and 30 after birth. A decrease in weight and height, as well as a decrease in the absolute and relative weight of the spleen of rat pups, was established. The above processes in the offspring of female rats with CTH were morphologically accompanied by a lag in the formation of structural and functional zones of the white pulp of the spleen and a lag in the development of T- and B-dependent zones of the spleen of rat pups in the dynamics of early postnatal ontogenesis