Abstract Aims The present study aims to elucidate the role of oxidative stress in erectile dysfunction associated with aging and to investigate the effect of treatment with vitamin E in this respect. Main methods Rats were divided into four groups: young (3-month-old), aged rats (18-month-old), aged rats given 80IU of vitamin E/rat/day for 21-days, aged rats given 5mg/kg of sildenafil/day for 21-days. Intracavernosal pressure/mean arterial pressure (ICP/MAP), nitric oxide production, TBARS, GSH levels and SOD activity in corpus cavernosum were measured. Key findings Significant decrease in ICP/MAP was observed in aged rats at both low and high frequency of stimulation. Significant increase in ICP/MAP was observed in aged rats treated with vitamin E over the range of 0.8 to 5Hz but young control values were not restored. Percentage potentiation of ICP/MAP than aged group at 0.8Hz was 326±41.3% and 897±72.2% for vitamin E and sildenafil respectively. Decreased levels of NO2/NO3 and SOD activity in the penile tissue observed with aging were elevated back to control by either vitamin E or sildenafil. Penile concentration of TBARS was 20.86±0.83 for aged rats vs. 11.39±0.79nmol/g tissue for young controls. Both vitamin E and sildenafil reduced penile TBARS in aged rats. Significance This study proves that antioxidant therapy with vitamin E ameliorates the age-associated erectile dysfunction. Sildenafil may exert some antioxidant properties which add to the advantages of its long-term use. The effect of combinations of low-dose sildenafil and vitamin E on age-associated erectile dysfunction merits to be studied.