Ninety-six healthy pregnant women and 249 women with gestosis were examined to compare the plasma levels of free amino acids in women with gestosis before and after delivery in order to estimate the degree of metabolic disturbances in this complication of gestosis. An amino acid analyzer was used to detect plasma free amino acids in the women at 36-40 weeks gestation and on day 6 postpartum. There was a direct relationship between the degree of gestosis and that of dysamino acidemia during pregnancy and postpartum. There was a marked reduction in the content of taurine (to 77%), arginine, aspartate, and isoleucine (to 50%) and аn increase in the level of proline (up to 95%) in gestosis as compared to these indicators in the control group. The formation of amino acid imbalance was established to play a significant role in pathogenesis.