Human erythrocyte catalase activity was studied involving the peroxidase reaction with ethanol and the reverse alcohol dehydrogenase reaction. The adequate kinetic parameters of the reaction were obtained under mild conditions of hemolysate preparation. Estimation of catalase activity in series of hemolysates enabled us to measure the activity values near 220.0 kU/ml of erythrocytes which corresponded to those in literature. Adaptation of the superoxide dismutase activity evaluation in erythrocytes was carried out using the basic system NADH-phenazine methasulfate-tetrazolium blue and the analyzer FP-901 equipped for nine simultaneous measurements. The rate of base reactions was plotted and the linear correlation was found between the reaction inhibition per cent and content of erythrocyte hemolysate and of commercially available preparation of superoxide dismutase. The procedures are simple and reproducible and may be used in routine studies of antioxidants.