The influences of different light condition, melatonin and epithalon on liver antioxidant system in 6-, 12-, 18- and 24-month-old rats of both sexes were studied. The activities of antioxidant enzymes as well as concentration of tocopherol demonstrate high stability. The maximal number of significant changes in antioxidant system parameters was found under continuous light exposure. Light condition, sex and preparation modulated age-related changes of antioxidant system.