BACKGROUND: We have today two treatment alternatives (orchiectomy or LHRH-analogue) in metastatic prostate cancer offering the same expectations of survival. This study documents the quality of life (QoL) and cost-effectiveness of these alternatives. PATIENTS AND METHODS: 65 consecutive patients treated at the University Hospital of Tromsø (UHT), Norway, between 1994 and 1999 were registered. At evaluation, 45 patients (LHRH-analogue--15 patients, orchiectomy--30 patients) were alive and included in the QoL-study (EORTC QLQ C-30, QoL 15D). 45 patients were followed-up at the UHT and included in the cost-analysis. Costs were calculated for a 36-month interval and converted to British pounds (1 Pound = 13 NOK). A 5% d.r. was employed. RESULTS: The mean QoL (15D) was 76.4 (orchiectomy) and 72 (LHRH) (0-100 scale). Constipation, urinating problems, fatigue, pain and loss of sexual functioning were the dominant symptoms. The treatment costs per patient treated were 8,895 Pounds (orchiectomy) and 10,937 Pounds (LHRH-analogue). The crossover in cost was located at 25 months. A sensitivity analysis varying discount rate (0-10%), drug charges (25-50% off) and treatment time (12-18 months) did not alter the conclusion. CONCLUSION: Orchiectomy is the treatment of choice when life expectancy is more than two years.