The purpose of this study was to investigate whether cholesterol plus methionine feeding may be a convenient model to produce atherosclerosis in rats, and also to examine the contribution of oxidative stress to this development. For this reason, lipid peroxide levels and antioxidant enzyme activities in the liver and aorta as well as histopathological findings were determined in male Wistar-albino rats fed a diet supplemented with cholesterol plus cholic acid and methionine for six months. This diet was found to increase lipid peroxide levels in the liver of rats. Hepatic glutathione peroxidase (GSH-Px) and catalase (CAT) activities increased, but superoxide dismutase (SOD) activity remained unchanged. In conclusion, cholesterol and methionine feeding in rats did not cause oxidative stress and atherosclerotic changes in the aorta, although hepatic prooxidant-antioxidant balance was affected by this diet.