INTRODUCTION:Osteoporosis is a common illness frequently leading to serious adverse outcomes for patients. Hip, wrist and vertebral fractures have considerable impact on both costs to healthcare system and lives of those who suffer from those events. Each year in the US, an estimated 1.5 million fractures occur due to osteoporosis [Riggs and Melton, 1995]. Estimated incremental cost of osteoporosis related events in subsequent years after fracture is US$4.007 [Rousculp, 2007]. Bisphosphonates are widely used and are considered an effective intervention for risk reduction of postmenopausal fractures. OBJECTIVES: The present study was conducted to compare the cost of bisphosphonates used for risk reduction of post-menopause vertebral and non-vertebral fractures under public payer (SUS) perspective in Brazil. METHODS: The most important bisphosphonates in the public market are ibandronate (oral and IV), zolendronate, alendronate and risendronate. There are no head-to-head clinical trials comparing all compounds. Studies of ibandronate IV [Eisman, 2008] and zolendronate IV [McClung, 2007] demonstrated their non-inferiority against oral bisphosphonates. Therefore, a cost-minimization approach was taken. Drug acquisition costs took into account was the maximum sales price to government. Administration costs were obtained from SUS reimbursement database (SIA/SUS, 2006). Since the time horizon of this analysis is one-year, no discount rate was utilized. Costs are presented in Brazilian Reais (US$1.00 ~ R$2.00 in May 2009). RESULTS: Total cost per patient was R$814.12 for IV ibandronate, R$915.59 for alendronate,  R$1054.32 for oral ibandronate, R$1054.97 for zolendronate and R$1278.81 for risendronate. Administration costs represented about 9% and 2% of total cost of ibandronate (administrated four times a year) and zolendronate (administrated once a year), respectively. CONCLUSIONS: Findings suggest IV ibandronate  is a cost-saving therapy with potential of reducing total treatment cost per patient from 11% to 36%, when compared to alendronate and risedronate respectively, under public payer perspective.