We report on a 50-year-old man with a liver mass that, when surgically resected, was found to be a hepatocellular carcinoma that had undergone spontaneous complete necrosis without previous treatment. Histologically, no viable tumor cells were observed. The postoperative course was uneventful, and the patient is alive without evidence of recurrence about 5 years after surgery. Spontaneous total necrosis of hepatocellular carcinoma without previous treatment is rare. In particular, spontaneous total necrosis of a hepatocellular carcinoma that has been proven by histologic examination of a surgically resected liver specimen is extremely rare; only three cases of spontaneous complete necrosis of hepatocellular carcinoma have been reported previously. In this report, we present our unusual case and discuss possible causes of spontaneous total necrosis or regression of hepatocellular carcinoma.