In this article the investigations of immune and interferon status in pregnant women with gestosis of the second half of pregnancy living in ecologically unfavourable zone are presented. In patients the content of M, G, A, CD antibody of populations of lymphocytes in serum, activity of lysozyme and complement, phagocytic activity,seruma and у interferon level was determined. High-grade depression of cellular immunity and interferon status was proved in pregnant women with gestosis, living in ecologically unfavourable zone.