Abstract: To investigate the diagnostic accuracy and clinical efficacy of combined CEA-CA19-9 serum values in patients with pancreatic cancer. The serum levels of CEA and CA19-9 in 108 patients with pancreatic cancer and 72 patients with benign pancreatobiliary disease were evaluated during four years. Two positive tests of CEA and CA 19-9 were assumed as positive and at least one negative test as negative. The sensitivity, specificity, accuracy, positive and negative predictive value and positive and negative likelihood ratio of the combined CEA-CA19-9 test were calculated in diagnosing pancreatic cancer. The sensitivity and specificity of CEA were 83.78 and 69.44%, respectively. When serum values of CA19-9 were investigated between two groups, 89.24% of sensitivity and 89.88% of specificity were detected. The combination of CEA and CA19-9 revealed the highest sensitivity (82.46%) and specificity (100%). After construction of Receiver Operating Characteristics (ROC) curve, the Area Under Curve (AUC) for CEA was 0.76 (95% CI; 0.68-0.83), whereas that for CA19-9 was 0.86 (95% CI; 0.78-0.91). Both values were acceptable for clinical investigations but the AUC of CA19-9 was statistically more than the related area for CEA (p = 0.006). The AUC for the model containing combined evaluation of CEA-CA19-9 was 0.91 (95% CI; 0.85-0.96). Present study revealed more diagnostic accuracy with serum CA19-9 than with CEA in detecting pancreatic malignancies, but the accuracy could not be raised statistically by combining these tumor markers.