Despite the proven efficacy of low-dose pamidronate in adults with osteoporosis, the efficacy of the low-dose regimen in children has not been studied. Pamidronate (1 mg/kg) was administered intravenously once every 3 months to 11 children with osteoporosis. Treatment was associated with reduced fracture rates and increased areal (BMD) and volumetric (BMAD) bone mineral density measured by dual energy X-ray absorptiometry (DXA). The mean annualized percent gain was 20.1 +/- 16.9 (4.7 to 59.1, n = 9) for spinal BMD and 15.1 +/- 18.1 (-11.0 to 40.2, n = 9) for spinal BMAD. Common adverse effects including fever, muscle aches, nausea and fatigue were self-limited and generally occurred only after the first infusion. Clinically significant hypocalcemia did not occur. Low-dose pamidronate appears promising in the treatment of childhood osteoporosis.