Background: Steroid-induced osteoporosis (SIO) is a serious complication of long-term steroid therapy and is of particular concern in growing children. Recently bisphosphonates have been applied in the treatment or prevention of SIO. We investigated the efficacy of pamidronate on SIO in childhood nephropathy patients receiving long-term corticosteroid therapy. Methods: Forty-four children receiving high doses of steroids were enrolled in the study. There was no history of bone, liver, or endocrine disease. Patients were randomly classified into two groups, the control group and the study group. All patients received corticosteroids for 3 months. Control group took oral calcium supplements (500 mg/day) only, and the study group oral calcium and pamidronate (125 mg) for 3 months. Biochemical tests, long bone radiography, and bone mineral density (BMD) were performed in the first month and 3 months later in all patients. Results: The differences in the results of biochemical tests such as serum calcium, BUN, and cre atinine level obtained in the first month and three months later were not of statistical significance in both the control and the study groups. However, the mean BMD of the lumbar spine decreased from 0.654 ± 0.069 (g/cm<sup>2</sup>) to 0.631 ± 0.070 (g/cm<sup>2</sup>) in the control group (p = 0.0017), while it did not in the study group from 0.644 ± 0.189 (g/cm<sup>2</sup>) to 0.647 ± 0.214 (g/cm<sup>2</sup>). Conclusions: Pamidronate appears to be effective in preventing SIO in children with nephropathy requiring long-term steroid therapy. Further long-term follow-up studies regarding the efficacy and side effects appear to be necessary to set a more solid basis for such pediatric uses of bisphosphonates such as pamidronate.