Objective: To investigate the expression of antiapoptosis gene bag1 and its relation to the differentiation of intrahepatic cholangiocarcinoma (ICC). Methods : Immunohistochemical techniques were adopted to study the expression of bag1 in ICC tissue ( n＝48) and parahepatocarcinoma bile duct (control group, n＝25). Results: Expression of bag1 in the ICC group was significantly higher than that in the control group. In the ICC group （P＜0.01）, the expression of bag1 in 21 cases of well differentiated ICC was significantly lower than that in 27 cases of middle and poor differentiated ICC （P＜0.01）. Conclusions: The expression of bag1 gene increases in the middle or poor differentiated ICC tissue suggests that bag1 gene might relate to the differentiation of ICC.