The aim of our study was to estimate the changes of superoxide dismutase (both isoenzymes: SOD-Zn, Cu and SOD-Mn in serum and total activity in erythrocytes) and gluthatione peroxidase (in erythrocytes) activities in newly diagnosed carbohydrate metabolism disturbances. 80 subjects were divided into two groups: the control with normal oral tolerance glucose test (OGTT) (n = 44) and investigated group (concentration of fasting glucose over 6.1 mmol/l and/or concentration of glucose in second hour of OGTT over 7.8 mmol/l) (n = 36). No differences of superoxide dismutase and gluthatione peroxidase activities as well as negative correlation between gluthatione peroxidase activity and concentration of glucose in second hour of OGTT (R = -0.28; p = 0.032) were observed. Falling tendency of gluthatione peroxidase activity in erythrocytes in subjects with postprandial hyperglycaemia suggest that this enzyme could be an early marker of antioxidant status of carbohydrate metabolism disturbances.