OBJECTIVES: This study describes the real-world healthcare resource utilization patterns for MPC patients treated by a urologist and/or an oncologist versus urologist only. METHODS: Health insurance claims (01/1999-02/2009) from 40 self-insured companies across the US were analyzed. Patients with a metastasis diagnosis (ICD-9: 196-199) following 2 prostate cancer diagnoses (ICD-9: 185, V10.46) within 365 days were identified. Patients with other malignant diagnoses were excluded. Patients were categorized in the ONCO group if they had ≥1 claim from an oncologist (± claims from urologist) and the URO group if they had claims only from urologist (i.e., no claim from an oncologist). Patients were evaluated for chemotherapy, hormonal agents, corticosteroids, supportive care, and hospitalizations during both baseline (defined as 365 days prior to metastasis diagnosis [index date]) and observation periods. RESULTS: A total of 1,661 URO and 1,131 ONCO patients formed the study population. At baseline, mean age was similar for URO and ONCO patients (72.3 vs. 72.8 years). During the baseline period, fewer URO patients received chemotherapy (3.8% vs. 7.3%), hormonal agents (45.1% vs. 63.1%), and corticosteroids (16.6% vs. 26.5%), compared to the ONCO group. The same trend was observed for supportive care therapies (URO vs. ONCO; biphosphonates: 4.8% vs. 10.5%; opioids: 33.4% vs. 41.8%). The rate of hospitalization at baseline was similar between groups. During the observation period, 13.4% of URO patients received chemotherapy, compared to 38.5% for ONCO patients. Similar differences were observed for the use of hormonal therapy (52.7% vs. 71.3%), corticosteroids (36.5% vs. 61.9%), and supportive care therapies (biphosphonates: 18.1% vs. 38.7%; opioids: 58.7% vs. 68.3%). Fewer URO patients had hospitalizations (62.4% vs. 72.8%) during the observation period. CONCLUSIONS: The findings from this observational study may contribute to the understanding of differing healthcare resource utilization patterns by physician specialty.