Bisphosphonates inhibit bone resorption and are widely used to treat osteolytic metastases and osteoporosis. Renal osteodystrophy patients have continuous bone loss due to chronically elevated parathyroid hormone (PTH). In this open-label study, ibandronate was evaluated for the treatment of reduced bone density in renal osteodystrophy. Patients (n=16) with end-stage renal disease (ESRD) and regular hemodialysis schedules were recruited. All patients had low bone mineral density (BMD; lumbar spine T-score <-1.0) and elevated PTH levels (>2-fold higher than normal). Patients received ibandronate 2 mg every 4 weeks for 48 weeks. Serum levels of markers of bone turnover, calcium, phosphate and magnesium were determined (week 0 [prior to treatment] vs. at week 48). BMD (n=11) increased significantly from 88.94 +/- 31.68 mg/mL calcium hydroxylapatite (CaHA) to 93.51 +/- 35.36 mg/mL CaHA (p=0.032). T-scores increased significantly from -3.08 +/- 1.11 to -2.78 +/- 1.27 (p<0.01). The mean PTH level initially increased before dropping to 18.99 pmol/L at week 48 (7.99% decrease vs. week 0; not significant). Bone turnover markers decreased, whereas calcium and magnesium levels remained stable and within normal ranges. Phosphate levels were variable throughout the study. Two patients did not complete the study, and 3 patients died due to concomitant cardiovascular disease. Calcitriol dosage increased from 1.5 to 1.83 microg/week. In patients with renal osteodystrophy and ESRD, ibandronate significantly increased BMD and decreased bone turnover.