OBJECTIVES: Patients with pain due to multiple bone metastases who do not show satisfactory response to conventional pain therapy radionuclide therapy leads to a pain reduction in about 70-80 % of patients. The objective here is to determine cost-effectiveness ratios for this pain reduction in Germany. METHODS: Based on the results of a double-blind, randomized, placebo-controlled trial with 141 prostate cancer patients radionuclide therapy is compared with conventional pain therapy in an economic model considering German data from literature and treatment recommendations. Incremental cost-effectiveness is presented. The effectiveness is measured by “complete pain response”. The model period is 16 weeks. Costs from the perspective of the statutory health insurance, i.e. deducting co-payments and discounts, are also considered. Sensitivity analyses are conducted. RESULTS: The direct medical costs of radionuclide therapy per patient (39% complete pain response) sum up to 1990€ against 2200€ under conventional pain therapy (17% complete pain response). Radionuclide therapy is dominant. From sickness fundsx perspective the costs of radionuclide therapy sum up to 1890€ compared to 1870€ under conventional pain therapy. The incremental cost-effectiveness-ratio is 130€ per complete pain responder. Sensitivity analyses reveal that the exclusion of bisphosphonates from conventional pain therapy lead to costs of therapy of 1170€. The respective incremental cost-effectiveness-ratio is 3800€ . From sickness funds' perspective the costs of conventional pain therapy sum up to 990€ . The respective incremental cost-effectiveness-ratio is 4210€. CONCLUSIONS: Analgesia in patients with pain due to multiple bone metastases is achieved at lower or nearly equal costs under samarium in the base case. On the basis of this model samarium could be a cost-effective treatment option for patients with pain due to multiple bone metastases. However, to compare cost-effectiveness ratios with other treatment options further research is warranted.