Aim Increases in oxidative stress and advanced glycation end‐products (AGE) formation play an important role in the pathogenesis of aging. Carnosine (CAR; β‐alanyl‐L‐histidine) has anti‐oxidant and antiglycating properties. We investigated the effect of CAR supplementation on AGE levels, and protein and lipid oxidation products in the serum and liver tissue in aged rats. Methods Young (3 months‐of‐age) and aged (20 months‐of‐age) rats were injected with CAR (250 mg/kg/daily; i.p.; 5 days per week) for 2 months. At the end of this period, AGE, protein carbonyl, advanced oxidized protein products, and malondialdehyde levels were determined in the serum and liver tissue. Furthermore, reactive oxygen species formation and ferric reducing anti‐oxidant power values were measured. Results AGE, malondialdehyde, protein carbonyl and advanced oxidized protein products levels, and reactive oxygen species formation were higher in the serum and liver tissue of aged rats compared with young rats. CAR treatment was observed to significantly decrease AGE, malondialdehyde, protein carbonyl and advanced oxidized protein products levels, and reactive oxygen species formation in the serum and liver of aged rats. Conclusions These results clearly show that CAR might be useful for decreasing glycoxidant stress in aged rats. Geriatr Gerontol Int 2017; ••: ••–••.