Two cell lines of human hepatoma, HLE and HLF lines, were established in vitro from the hepatocellular carcinoma of a 68-year-old patient. One clone (HLEC) was obtained from a single HLE cell. The cells of HLE and HLEC were epithelial-like and both of these cells demonstrated glycogen granules in the cytoplasm when stained with periodic acid and Schiff reagent. Although HLF cells resembled fibroblasts in morphology, they appear to have originated from hepatoma cells, judging from epithelial characteristics in aggregates reconstituted by rotation culture and heterotransplantability. HLE cells produced alpha-fetoprotein until day 187 of culture, but HLF cells did not produce alpa-fetoprotein at any period examined. Chromosome number of both cell lines was distributed near the triploid range. HLF cells were transplantable into the cheek pouch of adult hamsters treated with cortisone acetate, but not HLE cells.