Objective:To investigate the expression of insulin-like growth factorⅡ mRNA binding 3(IMP3) and its clinical significance. Methods:Paraffin sections of tumor tissues,pericarcinomatous tissues and normal tissues from 54 patients with cholangiocarcinoma were examined for expression of IMP3 by immunohistochemistry. Detect IMP3 expression by Western blot in different pathological grades,including five cases of gradeⅠ,4 cases of gradeⅡ and 5 cases of gradeⅢ. Tumor tissues,pericarcinomatous tissues and normal tissues from 17 patients with cholangiocarcinoma were examined for expression level of IMP3 mRNA by quantitive real time PCR. Follow and count long-term survival of 47 patients with post-operation of cholangiocarcinoma.Results:IMP3 expression was positive in 81.84% of cholangiocarcinoma,negative in pericarcinomatous tissues and normal tissues. Significant differences of IMP3 expression among different pathological grades,the higher grade,the higher IMP3 expression levels. The mRNA level of IMP3 was also increased in tumor tissues,and there was correlation with protein level. The follow up of forty-seven postoperative cases found the postoperative long-term survival of IMP3 negative group was significantly higher than that of the IMP3-positive group(P < 0.01). Conclusion:IMP3 can be used as a new marker for the diagnosis of cholangiocarcinoma,higher pathological grade,the higher degree of malignancy,the higher expression level. The overexpression of IMP3 suggests poor prognosis.