The study comprised 35 patients with mixed hyperlipidaemia and coronary heart disease (CHD) risk factors (overweight or obesity, low physical activity, family history). Seventeen patients were administered atorvastatin in a dose of 10 mg and 18 -fluvastatin in a dose of 40 mg once daily at bed time for 6 weeks. The control group consisted of 12 clinically healthy subjects with no CHD risk factors. Blood samples for testing were collected from cubital vein of patients after hypolipaemic diet prior to and 6 weeks after drugs application and once in control group. Malondialdehyde (MDA) concentrations in erythrocytes and plasma were determined by the method of Placer et al. MDA concentrations in erythrocytes and plasma were significantly higher (p < 0.05) in patients than in healthy subjects. After 6-week atorvastatin therapy MDA concentrations in erythrocytes and plasma decreased to the values observed in healthy subjects. In fluvastatin group erythrocyte and plasma MDA concentrations were unchanged and still significantly higher in comparison to the healthy subjects. Atorvastatin, contrary to fluvastatin, decreases lipid peroxidation in CHD risk patients.