Metastatic spread of prostate cancer to the peritoneum is rare but may be either due to an iatrogenic cause or a sign of a more aggressive disease. We present a patient with peritoneal carcinomatosis who survived prostate and colon cancer. A 72-year-old male presented with abdominal pain, weight loss, and abdominal distension. He was treated surgically for prostate cancer and colon cancer in the past. Investigations revealed liver and peritoneal metastases, and the liver biopsy suggested that the lesions were of colorectal origin. The patient had a good response after 18 cycles of systemic chemotherapy, allowing cytoreductive surgery (CRS) and hyperthermic intraperitoneal chemo- therapy (HIPEC) to be performed. Pathological examination of tissues removed during surgery revealed the prostatic origin of the peritoneal nodules. The final diagnosis altered his adjuvant treatment and may have implications for his post-operative monitoring. CRS and HIPEC could improve survival but there is no established regime for prostatic peritoneal metastases. However, the use of regimes applied to other primaries has been reported. Personalisation of treatment using novel technologies could potentiate treatment benefits.