Supplementation of branched-chain amino acids (BCAAs) is often used for the treatment of hepatic encephalopathy and low albuminemia in Japan. In this scenario, although many cases are complicated with hepatocellular carcinoma in chronic viral infection, the effect of BCAA levels on hepatocellular carcinoma cells remains unclear. We investigated the effect of the molar ratios of BCAAs to aromatic amino acids (AAAs) on the growth and albumin mRNA expression of cultured human liver cancer cell lines, HCC-M, HCC-T, PLC/PRF/5, and Hep G2. To exclude the effect of fetal serum in culture media on modification of the growth and albumin transcription of cell lines, we used a synthetic serum-free medium. We found that an increase in the molar ratio of BCAAs to AAAs reduced the growth of Hep G2 cells, and it increased albumin mRNA expression in this cell line at a molar ratio of 0.1-10. These results suggest that the molar ratio of BCAAs to AAAs affect the growth and mRNA expression of some liver cancer cells, and supplementation of BCAAs may at least be beneficial to patients with cirrhosis, even complicated with liver cancer.