to investigate the expression of c-jun-activation-domain binding protein (JAB1) in hepatocellular carcinoma (HCC) and the clinicopathologic significance thereof. Immunohistochemistry was used on 76 specimens of HCC tissues and native liver tissues adjacent to the HCC tissues, and 10 specimens of normal liver tissues near the liver angioma to detect the expression of JAB1 and the cell proliferative factor Ki67. The expression rate of JAB1 in the HHC tissues was 68.85%, significantly higher than that in the adjacent liver tissues and normal liver tissues near liver angioma (38.72% and 34.36% respectively, both P < 0.001). The expression of JAB1 was correlated with the histological differentiation, serum alpha-fetoprotein level, and metastasis (P = 0.000, 0.015, and 0.000), but not with gender, age, tumor size, serum HBsAg, and existence of necrosis and cirrhosis. The expression rate of Ki67 protein in the HCC tissues was 41.45%, significantly higher than that in the adjacent liver tissues and normal liver tissues near liver angioma (2.11% and 2.01% respectively, both P < 0.001). There was a positive correlation between JAB1 and Ki67 (P < 0.001). JAB1 is highly expressed in HCC and may play an important role in the oncogenesis and development of HCC. JAB1 may be used as a marker for neoplastic change in liver cells and thus has potential clinicopathologic value.