The aim of this work was to study the ultrastructure of the internal pyramidal neurons of the neocortex of 5-day-old rat pups after antenatal alcoholization. The studies were carried out on female outbred white rats with an initial weight of 230 ± 20 g and their offspring. Prenatal alcoholization causes deep and varied ultrastructural changes in pyramidal neurons in the neocortex of 5-day-old rats. Moreover, these violations of direct action not only as a consequence of the damaging effect of alcohol, its metabolite acetehyde or the oxidative stress they cause on the membranes and organelles of neurons during embryogenesis, but also as a violation of the normal "program" of development" of neurons in the cortex.