Alendronate is an aminophosphanate, selective inhibitory of bone resorbtion, used for treatment of osteoporosis in postmenopause. It is known that changes occurring in postmenopausal period effect the quality of life. In this study, effect of the alendronate treatment time on renal oxidative status was investigated in ovariectomized rats. Alendronate was intravenous administered at 0.3 mg/kg dosage on weeks 2, 4 and 8. Serum creatinine and uric acid levels and kidney malondialdehyde (MDA), glutathione (GSH), catalase (CAT), superoxide dismutase (SOD) and myeloperoxidase (MPO) level and activities were measured. Serum creatinine and uric acid levels increased in depending on the time of alendronate treatment on ovariectomized rats. Kidney MDA level and MPO activity increased in both ovariectomized and alendronate groups. Kidney GSH level and SOD and CAT activities decreased in the ovariectomized rats and these levels increased in depending on time of alendronate treatment. As a result, some oxidative changes occurred in the kidney tissue of ovariectomized rats with bone resorption and alendronate treatment increased the antioxidant capacity in depending on the time.