Objective To evaluate the value of serum CA 19-9 levels in predicting resectability of pancreatic cancer. Methods Serum CA 19-9 levels of 52 patients with pancreatic cancer who were possible to be curatively resected according to the imaging were determined; the gold standard was respectability. An receiver operating characteristic (ROC) curve was constructed for the CA 19-9 levels; the point that lies closest to the upper left-hand comer of the graph is chosen as the cut-off point, the sensitivity, specificity,positive and negative predictive values were calculated. Results There were 29 (55.8%) resectable and 23 (44.2%) inoperable cases of pancreatic cancers. The CA19-9 level in resectable patients was (159.6±170.9)U/ml, and it was (944.4 ±773.4) U/ml in inoperable cases. The area under the ROC curve was 0. 918 ( ＞ 0.9, P ＜ 0.01 ), 95% confidence interval were 0.843 ～ 0.992. The CA19-9 level was (353.2) U/ml according to the cut-off point, the sensitivity and specificity was 93.1% and 78.3%, respectively; positive and negative predictive values was 84. 4% and 90. 0% , respectively. Conclusions Preoperative serum CA19-9 level may be a useful marker for further evaluating the respectability of pancreatic cancer who are possible to be resected according to the imaging studies.