OBJECTIVES: To compare annual management costs of castration-resistant prostate cancer (CRPC) patients at high risk of developing bone metastases (BM) versus those that already had BM in Spain. METHODS: An expert panel of 5 urologists and 3 oncologists from Spanish health centres was asked to estimate the mean annual resource use in the management of non-metastatic CRPC patients and in the first, second and subsequent years after developing BM. Hospital resources were stratified into four major categories: 1) general resources [medical visits, diagnostic and monitoring procedures, hospital admission and surgeries], 2) hormone therapy, 3) chemotherapy and 4) analgesic treatments. The last three categories included: drug costs, adverse event (AE) management-costs and pre-medication costs. Skeletal-related events (pathological fracture, radiation or surgery to bone and spinal cord compression) often suffered by BM patients were excluded from the analysis as Spanish cost-related data had recently been published. Unit costs (€, 2013) for each identified resource were obtained from a national cost-database. RESULTS: Total management-related annual costs for non-metastatic CRPC patients were €2,691.57; €978.51 were hormone therapy drug costs, €11.10 analgesics costs and €243.55 AE management costs. No chemotherapy was administered in these patients. Annual management cost for BM patients was €6,000.37 the first year, €14,468.35 the second year and €14,313.87 in subsequent years. Hormone therapy drug costs accounted for €946.67, €948.13 and €948.13 in the first, second and subsequent years, while chemotherapy costs accounted for €1,892.21 (32.2%); 9,485.41 (66.2%) and €9,143.92 (64.4%), respectively. Analgesic costs increased from €597.29 (first year) to €915.16 and €1,031.20 (second and subsequent years) and AE management costs increased from €595.63 (first year) to €758.58 (second year) and €732.14 (subsequent years). CONCLUSIONS: CRPC patients with BM had higher management costs than non-metastatic patients especially after the first year of treatment, which was mainly due to chemotherapy drug costs.