Inhibition of glycogen and glucose synthesis as well as of hexokinase and lactate dehydrogenase activities and an increase in content of lactate were found in rats after repeated (within 7 days) and chronic (within 35 days) hypoxic treatment ("height 9000 m, daily exposure in an altitude chamber during 6 hrs). Exhaustion of glycogen stores in lungs developed while the chronic hypoxia was maintained. Sex variations were observed in the main patterns of carbohydrate metabolism in lungs. Under conditions of chronic hypoxia content of glucose was higher and the hexokinase activity was lower in lungs of female rats as compared with that of male rats.