This first case of mucoepidermoid carcinoma of the liver to be reported was discovered in a 44-year-old man with an 8-month history of fever, vomiting, weight loss (15 kg.), and pain in the right hypochondrium. A right hemihepatectomy disclosed a 15 cm. tumor located above the gallbladder bed. Histologically, the growth was composed of nests of epidermoid and mucus secreting cells, sometimes with cystic spaces in the center of the nests. Intercellular bridges and keratinization were present in the epidermoid parts of the tumor. The mucus-secreting cells were periodic acid-Schiff and Alcian blue positive. Necropsy revealed no remaining tumor or metastases in other organs. It is suggested that epidermoid elements may arise from the biliary ducts as they do from salivary ducts.