The effects of radiation emitted from cellular phones oil humans are an emerging area of investigation. The previous studies have shown the role of oxidative stress and NO at radiofrequency exposed rats. Therefore, the purpose of this study was to investigate the effect of microwave /radio/frequency emitted from mobile phones and its possible oxidative damage. Wistar Albino rats were divided into three groups as exposure, sham and cage control. Rats in exposure group were exposed to 900 MHz microwave radiation (0.0782 in W / cm(2)) in a carousel for 2 hours/7 days in a week during ten months. The same process was applied to sham group but the generator was turned off Rats in cage control group were kept ill cage only during the study The levels of catalase (CAT), myeloperoxidase (MPO), malondialdehyde (MDA), total antioxidant capacity (TA C), total oxidant status (TOS), oxidative stress index (OSI) in liver and nitric oxide (NO) levels in serum were determined to demonstrate the role of oxidative mechanisms. The increase of nitric oxide levels in exposure and sham groups were found significant compared to cage control group (p<0.01, p<0.05). Although serum NO levels increased in exposed rats, the difference between exposure and sham groups was not significant (p>0.05). MDA and TOS levels in liver tissue were found higher in exposed group compared to sham and cage control group (p<0.05). However, no significant alterations were found in other endpoints such as CAT MPO, TA C and OSI. In this study we showed that 900 MHz radiofrequency radiation emitted from mobile phones exhibited an increase oil MDA and TOS levels. Therefore, RF radiation emitted from GSM cellular phone may play a role to induce oxidative damage by; increasing lipid peroxidation and oxidative stress.