Background: Despite a lack of up-to-date clinical trial data, many clinicians advocate the use of Carboplatin monotherapy to treat patients with advanced Castrate Resistant Prostate Cancer (CRPC) who have exhausted multiple other treatment options. The aim of this study was to determine the overall survival (OS) and response rate in patients with advanced CRPC treated with Carboplatin monotherapy after progressing on other chemotherapy agents. Methods: Retrospective multicentre study of the use of Carboplatin in advanced CRPC patients in Australia. Demographic data, PSA response rates, survival data and Carboplatin treatment protocols, such as dose and duration, were collected. Exploratory analyses on potential prognostic parameters were performed. Results: 51 patients received Carboplatin: median age 68 (range 55–86 years). Most patients (78.3%) received Carboplatin AUC 5 at 3-weekly intervals. The median number of cycles of Carboplatin was 3 (range 1-17). Median time on treatment was 63 days (range 1-441). Median overall survival was 29.4 weeks (IQR 11.7 weeks). 6 (11.8%) patients had a PSA response ≥50%. The median time to PSA progression on Carboplatin was 67 days (range 15-418). 16 patients (31%) required a dose delay or reduction and 8 patients (15.6%) ceased Carboplatin secondary to side effects/ toxicity. Conclusions: Our findings demonstrate that in heavily pre-treated CRPC, Carboplatin has a modest benefit in a minority of patients with a low rate of toxicity in the advanced prostate cancer population.