The objective of this study was to investigate the effect of Bisphosphonate on osteoporosis in patients undergone kidney transplantation. 40 candidates of kidney transplantation, aged more than 20 years old, with low bone mineral density (T-Score < -2) in spine, total femur, or femoral neck, regardless the cause of end stage renal disease, were randomly assigned to receive Pamidronate or Alendronate. Pamidronate was administered as 90 mg infusions at the beginning and after three months. Alendronate, 70 mg orally, was administrated weekly for 6 months. Drug administration began in the third week for both groups. Both groups received standard treatment protocol including Prednisolone, Cyclosporine, and Mycophenolate Mofetil. Bone mineral density was measured via dual-energy x-ray absorptiometry (DXA) by a trained technician with a single instrument at the beginning and 6 months later. Plasma level of Parathormone hormone (PTH) was assessed at the beginning and at the end of study. Plasma level of calcium, phosphorus, alkaline phosphatase, blood urea, creatinine, and cyclosporine were measured monthly.