Urachal adenocarcinoma is an uncommon clinicopathologic entity associated with a dismal prognosis. We report a case of peritoneal carcinomatosis from urachal adenocarcinoma (signet cell type) treated with cytoreductive surgery and intraperitoneal hyperthermic chemotherapy (IPHC). Prior to treatment, disease had progressed with systemic chemotherapy. The patient remained free of symptomatic peritoneal disease or local recurrence but eventually died 23 months after IPHC and 31 months after diagnosis due to widespread bone metastases.