The results of this study suggested that long-term treatment with strontium ranelate over 5 years is cost-effective compared to no treatment for postmenopausal osteoporotic women. INTRODUCTION: This study aims to estimate the cost-effectiveness of long-term strontium ranelate treatment for postmenopausal osteoporotic women. METHODS: A validated Markov microsimulation model with a Belgian healthcare cost perspective was used to assess the cost per quality-adjusted life-year (QALY) of strontium ranelate compared to no treatment, on a basis of calcium/vit D supplementation if needed. Analyses were performed for women aged 70, 75, and 80 years either with a bone mineral density T-score = -2.5 SD or with prevalent vertebral fractures. The relative risk of fracture during therapy was derived from the Treatment of Peripheral Osteoporosis Study trial over 5 years of treatment. Parameter uncertainty was evaluated using both univariate and probabilistic sensitivity analyses. RESULTS: Strontium ranelate was cost-saving at the age of 80 years in both populations. For women with a T-score = -2.5 SD, the costs per QALY gained of strontium ranelate were respectively 15,096 and 6,913 at 70 and 75 years of age while these values were 23,426 and 9,698 for women with prevalent vertebral fractures. Sensitivity analyses showed that the results were robust over a wide range of assumptions. CONCLUSION: This study suggested that, compared to no treatment, long-term strontium ranelate treatment is cost-effective for postmenopausal osteoporotic women.