Hepatocellular carcinoma is a primary malignancy of hepatocytes which accounts for 80 % of all primary liver cancers. DFNA5 has been identified as a tumor suppressor gene with an important role in several frequent forms of cancers, while little is known about its role in hepatocellular carcinoma. Through comparison of the DFNA5 protein expression in hepatocellular carcinoma cells (HepG2) with human fetal lung fibroblast cells (MRC5), we found that the DFNA5 protein expression in hepatocellular carcinoma cells was significantly lower than that in normal cells. The transfection of DFNA5 gene into HepG2 cells could increase DFNA5 protein expression, which subsequently led to inhibition of cell proliferation. Underlying mechanism study revealed that decreased proliferation was due to increased apoptosis and cell cycle arrest. In view of the important role of DFNA5 gene in carcinogenesis, these findings are expected to provide new understanding on development and treatment of human hepatocellular carcinoma.