collected from healthy non-smoking women living in the high polluted region, i.e. the Copper Mining Territory (CMT) and the 38 control placentas (C) obtained from little polluted eastern Carpathian regions. The placentas were studied by histochemical, immunohistochemical and morphometric methods. In CMT placentas a decrease in the cytochrome c oxidase and glucose-6-phosphate activities and the immunoreactivity of glutathione S-transferase pi in the villous syncytiotrophoblast and amniotic epithelium was noted. All CMT placentas showed abundance of mineral and fibrinoid deposits and of lipid droplets. This produced a compensatory increase in the mother-fetus exchange area due to excessive proliferation of placental villi which in turn decreased the intervillous space and thus the influx of indispensable maternal blood. Lately slight signs of increase in the cytochrome c oxidase activity accompanied by a noticeable decrease in number of the thinnest (most abundant) terminal villi is observed.