Since radiation therapy has been known to be a cause of bone atrophy (radiation osteopathy), it could be important whether postoperative radiotherapy in patients who have undergone oophorectomy further promotes bone mineral loss or not. Nineteen patients with stage Ib to IIb cervical cancer were studied. Eleven of the 19 patients received only surgical treatment and 8 received postoperative radiotherapy (50 grays to the pelvis and 40 grays to the lumber spine), because of the presence of advanced lesions or positive lymphnodes. A significant increase in FSH and decrease in E2 (p less than 0.01) compared to before treatment were observed in both groups. A significant increase in serum alkaline phosphatase activities (p less than 0.01), urine-calcium/creatinine ratio (p less than 0.05) and urine-hydroxyproline/creatinine ratio (p less than 0.01), which indicated high bone turnover, compared to before treatment in both groups also appeared. Although these chemical parameters in both groups changed coincidentally, the decline in spinal bone mineral density in the irradiated group was delayed at 12 months after the treatment. On the other hand, there was no difference in the changes in femoral bone mineral density in the two groups. These results suggest that radiotherapy might inhibit the bone mineral loss at the irradiated bone site even when there was an estrogen lack.