In this work we present these histological examination of the kidneys of pregnant females Caspian seals and their fetuses. In the renal tissue of Mature females seals were marked signs of chronic glo- merulonephritis and amyloidosis. These diseases was accompanied by the following histopathological manifestations: necrosis of epithelial layers, basal membranes, walls convoluted tubule, hypercellularity in the renal corpuscles, significant growths of connective tissue in the walls of the renal vessels and along the arterioles, microcirculatory disorders (hemo - and plasturgie), sediment masses of amyloid in the walls of blood vessels and in the renal corpuscles. In embryos in the kidneys revealed the following violations: hyperemia of the capillaries of the glomeruli, the narrowing of the urinary space; degeneration of the cytoplasm of epithelial cells of the tubules; necrosis of epithe- lial cells and tubule; the detachment of the epithelial layer from the basal membrane. Identified deficiencies in the system «mother–fe- tus» indicate a decline in the functionality of the excretory system.