A rare case of hepatocellular carcinoma who developed the complication of the sign of Leser-Trelat is reported. The patient, a 57-year-old male, visited our hospital with complaints of generalized malaise and anorexia. A diagnosis of hepatocellular carcinoma was made based on elevated alpha-fetoprotein measurement, ultrasonography, and hepatic arteriography findings. Chest x-ray film suggested pulmonary metastases of hepatocellular carcinoma. Thereafter, complications of the seborrheic keratosis developed in the trunk and the skin lesion was diagnosed as the sign of Leser-Trelat associated with hepatocellular carcinoma. The patient died of pneumonia 9 months after development of the sign of Leser-Trelat.