OBJECTIVES: Active case finding for osteoporosis is increasingly popular. However, it is not known if subjects, once identified as having osteoporosis, are willing to take preventive drug treatment, and what determines this willingness. We investigated patients' preferences for preventive osteoporosis drug treatment in a discrete choice experiment. METHODS: A discrete choice experiment (DCE) was administered to community dwelling females aged over 60 years (n=120; including women with high fracture risk (n=60)), identified by osteoporosis case finding in 34 GP-practices in and around Rotterdam. We investigated the effects on acceptance of preventive drug treatment of treatment effectiveness, side effects (nausea), total treatment duration, route of drug administration, and costs. The relative importance of the treatment attributes, the trade-offs that elderly women are willing to make between these attributes, and willingness to pay were estimated using conditional logistic regression analysis. RESULTS: All treatment attributes were important to respondents (p<0.05). Absence of side effects of drug treatment was the most important treatment attribute of treatment acceptance. The negative utility of side effects such as nausea was totally compensated for when the drug reduced the relative lifetime risk of hip fracture by 35% or more. Women were prepared to pay an out-of-pocket contribution if the treatment was coherent with their preference. CONCLUSION: Women identified by active osteoporosis case finding are highly prepared to adhere to preventive drug treatment, even if side effects (nausea) are expected and some out-of-pocket contribution is required.