Oxidative stress plays an important role in aging. Effects of several antioxidants on age-related oxidative stress have been investigated. Carnosine (CAR) and betaine have antioxidant actions. The combination of CAR with vitamin E(CAR+E) increases its antioxidant efficiency. We investigated the effects of CAR+E and betaine treatments on oxidative and antioxidative status in liver, heart and brain tissues of aged rats. Experiments were carried out on young (5 months)and aged (22 months) male Wistar rats. Aged rats were given CAR (250 mg/kg; i.p.; 5 days per week) and vitamin E (200mg/kg; i.m.; twice per week) or betaine (1% w/v) for two months. Malondialdehyde (MDA) and diene conjugate (DC)levels and antioxidants were measured. MDA and DC levels were higher in tissues of aged rats than young rats. Glutathione(GSH) levels decreased in liver, but not heart and brain. There were no changes in vitamin E and vitamin C levels and superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and glutathione transferase (GST) activities in tissues of aged rats. CAR+E treatment was observed to decrease MDA and DC levels in tissues of aged rats. However, betaine decreased only hepatic MDA and DC levels. Both CAR+E and betaine increased hepatic GSH and vitamin E levels, but these treatments did not affect antioxidant enzyme activities. These results suggest that CAR+E treatment seems to be useful to decrease oxidative stress in liver, heart and brain tissues, but betaine is only effective in liver tissue of aged rats.