OBJECTIVES: Define the treatment patterns and associated costs to treat metastatic prostate cancer in Brazilian private health care system. METHODS: In a nationwide oncology claims database of 3.5 million lives, from August 2010 to July 2011, 67 patients were identified with metastatic prostate cancer using chemotherapy. Patients using hormone therapy were excluded. The database gathered information regarding the treatment patients were submitted, to average duration and medication dosage.  RESULTS: Patients were on average 71 years old, weighted 78 kilograms and measured 1.70 meters. Among the 67 patients, only 5 (7%) were submitted to first line treatment with mitoxantrone and 62 (93%) with docetaxel; 58% of all patients took a second line treatment. From the 62 patients that started with docetaxel (121.5 mg average dose for each of the 6.5 cycles (21days)), 28 had a second line treatment with mitoxantrone (20mg average dose for each of the 3.9 cycles (21days)) with total average cost/patient of R$ 39,698 (USD 22,056); 7 were retreated with docetaxel (60mg average dose for each of the 6 cycles (7days)). From the 5 patients that started with mitoxantrone (20.6mg average dose for each of the 3.2 cycles (21 days)), 4 continued the treatment with docetaxel (60mg average dose for each of the 3 applications (21 days)) with a total average cost/patient of R$ 12,795 (USD 7,107). CONCLUSIONS: The database suggests that docetaxel is the most commonly used first line treatment to metastatic prostate cancer in the Brazilian private health care system. Forty-two percent of the patients were not submitted to a second pattern in the period studied, being that 18% of the ones that had a second line treatment were retreated with the same medication (docetaxel).