The activity of carbohydrate metabolism certain enzymes [hexokinase (EC 2.7.1.1.), glucokinase (EC 2.7.1.2), phosphofructokinase (EC 2.7.1.11.1), glucoso-6-phosphate-dehydrogenase (EC 1.1.1.49.)] was studied in the sheep skin when adding vitamin A, sodium sulphate and insulin to the basic ration. The activity of the studied enzymes in the skin was established to be rather high and depend to a considerable extent on feeding, seasonal and hormonal factors. In summer the activity of such enzymes as glucoso-6-phosphate-dehydrogenase and glucokinase decreases, and that of hexokinase, vice versa, increases. Vitamin A alone against a background of the basic ration almost has no effect on the activity of the enzymes, with the exception of phosphofructokinase in certain periods of the experiment. More noticeable shifts in the activity of the enzymes were observed in the case when vitamin A and sodium sulphate were added to the ration of sheep, and also with the injection of insulin. In such cases in the sheep skin there occurs first of all an increase in the activity of glucokinase and glucoso-6-phosphate-dehydrogenase.