Peritoneal seeding with no further metastases of prostate cancer is very rare. To the best of our knowledge, there are only three cases reported in the available literature. There has not yet been a report of a patient undergoing robot-assisted laparoscopic radical prostatectomy (RALRP) that might have resulted in peritoneal seeding. We describe a patient who presented with a prostate-specific antigen (PSA) recurrence and who was found to have a solitary metastasis on the liver, 2 years after RALRP. The patient underwent open excision of the mass, which was densely adherent to the liver. Pathologic examination revealed metastatic adenocarcinoma, which stained positive for PSA. Our patient represents an unusual case of a surgically documented peritoneal seeding of prostate adenocarcinoma during RALRP.