A 75-year-old cirrhotic man, after undergoing percutaneous acetic acid injection therapy for hepatocellular carcinoma, presented high fever and right hypochondralgia. Computed tomography disclosed an area of low attenuation in the liver and a crescent-shaped intraperitoneal lesion adjacent to it. We diagnosed liver perforation and localized peritonitis due to the leakage of acetic acid following acetic acid injection. It is important to consider this serious complication when evaluating the indications for percutaneous acetic acid injection for hepatocellular carcinoma.