OBJECTIVE: Hip fracture rates in Taiwan have been reported to be higher than other Asian countries. The objective of this analysis was to assess the cost-effectiveness of risedronate compared to alendronate in high-risk osteoporotic patients in Taiwan. METHODS: A fracture-incidence based Markov model of osteoporosis, where patients transition across states, was used to estimate cost per fracture averted and cost per QALY gained. The population included 1000 women aged 65 years with low bone density and previous vertebral fracture, treated over a lifetime with either risedronate or alendronate. Model inputs specific to Taiwan included general population hip fracture rates, mortality rates, health utilities, and relative risk reduction of fracture with therapy (from published studies). The launch price of risedronate was anticipated as 20% higher than alendronate (risedronate: 16,394 NT$/year; risedronate 13,662 NT$/year). Vertebral fracture rates were not available for Taiwan, thus incidence rates were based on US ratios of hip to vertebral fracture. The cost of fracture was included only for first year after fracture since chronic treatment is not routine in Taiwan. RESULTS: There were 58 fewer hip fractures, 35 fewer vertebral fractures and 52 more QALYs with risedronate compared to alendronate. The fracture costs were 15% lower for patients treated with risedronate, however total costs (including drug costs) were higher (259,358 NT$ [risedronate] vs. 227,296 NT$ [alendronate]). The incremental cost was 343,225 NT$ (8,400€) per any fracture averted, 552,787 NT$ (13,500€) per hip fracture averted, and 617,934 NT$ (15.100€) per QALY gained for risedronate compared to alendronate. CONCLUSIONS: Risedronate treatment for high-risk osteoporotic women may represent a cost-effective strategy for improving care of patients in Taiwan, despite the fact that there are fewer downstream costs for treatment of chronic fracture-related disability.