OBJECTIVES: To evaluate the preferences of osteoporotic patients for medication attributes in Belgium and Ireland, and to assess whether preferences are transferable across these jurisdictions. METHODS: A discrete-choice experiment was designed in which patients were asked to choose between two unlabelled drug alternatives (and an opt-out option), which vary in five attributes: efficacy in reducing the risk of fracture, type of potential common side-effects, mode and frequency of administration and out-of-pocket costs. An efficient experimental design was used to construct the sets of treatment options and a mixed logit panel data model was employed to estimate patients’ preferences. To assess the significance of the differences between countries, a joint model was estimated using interaction terms. RESULTS: A total of 257 Belgian and 200 Irish osteoporotic patients completed the experiment. In both countries, patients preferred a drug treatment with a higher risk reduction and a lower cost. They disliked more being at risk of gastro-intestinal disorders than at risk of skin reactions and flu-like symptoms and preferred 6-month subcutaneous injection compared with weekly oral tablets. In Belgium, patients also preferred oral monthly tablet over weekly tablets, while Irish patients preferred yearly intravenous over weekly tablets. Some differences between countries were significant. Irish patients attached higher value to being at risk for skin reactions or flu-like symptoms, and the parameter of yearly intravenous was higher (and significant) in Ireland. In addition, higher costs are more acceptable for Irish patients. These differences were generally robust in subgroups analyses including patients over 65 years, with prior fracture, high income or high education. CONCLUSIONS: In this study, the preferences of osteoporosis patients for drug therapy did not substantially differ between two European countries. Only for levels of some attributes significant differences were observed, which could not only be related to health and socio-demographic factors.