Objective:To explore the association between diabetes mellitus(DM) and risks of extrahepatic cholangiocarcinoma (ECC) by meta-analysis. Methods:Databases of Chinese CNKI, Wanfang, Medline, EMBASE were searched for the articles on the relationships of DM and ECC risk from databases establishment to September 2010;Adjusted relative risks(RRs) and their corresponding 95% confidence intervals(95%CI) were calculated using a random-effect model;Potential sources of heterogeneity between studies were explored and publication bias was evaluated. Results: DM was associated with an increased risk of ECC,with pooled OR=1.62(95%C1=1.05~2.49) for case-control studies and pooled RR=1.54(95%C1=1.06~2.23)for cohort studies. The significant heterogeneity was mitigated in some of the subgroup analyses and publication bias was not significantly in the studies(Egger’s test,P = 0.798;Begg’s test,P = 0.548). Conclusion: The present study suggests that DM may be a high risk factor for ECC.