OBJECTIVES: A cost minimization analysis was developed to compare the costs of intra-venous biphosphonates therapies available in Brazil for preventing skeletal events (SE) in breast cancer patients with bone metastasis. METHODS: Indirect comparison of different clinical trials published do not allow us to consider that exist an efficacy difference among ibandronate acid, zoledronic acid and pamidronic acid (e.g.: Body et al. 2004; Rosen et al. 2003; Theriault et al. 1999). In our analysis only direct costs were considered. The indirect costs of treating SE were not estimated. For direct costs calculations we assumed the reduction in analgesics usage reported by De Cock et a. 2005 (Ibandronic acid: 7% reduction vs. Comparators: 3% reduction). The time horizon of the analysis was 14 months which represents the average overall survival of patients (Hotton J et al, 2004). Therefore discounting was not applied. The payer perspective was adopted under the Brazilian setting. A one-way sensitivity analysis was conducted. RESULTS: Results show that ibandronic acid offers the lowest treatment cost, followed by pamidronic acid and zoledronic acid (R$ 10,301, R$ 10,906 and R$ 12,829). Results were sensitive to drug prices. CONCLUSION: Results suggest ibandronate acid as a cost-saving alternative with better safety profile when compared to zoledronic acid and pamidronic acid under the Private Healthcare System perspective in Brazil.