Abstract: Objective: To evaluate the clinical significance of serum tumor markers carbohydrate antigen 19-9(CA19-9),carbohydrate antigen 242(CA242) and carcinoembryonic antigen (CEA) in differential diagnosis of benign and malignant obstructive jaundice. Methods: Serum levels of CA199,CA242 and CEA were detected by radioimmunoassay in 88 patients with malignant obstructive jaundice and 52 patients with benign obstructive jaundice. The receiver-operating characteristics curve (ROC) of the three serum tumor markers was made and the areas under the curve (AUC) were calculated. The sensitivity,specificity,positive predict value,negative predict value,positive likelihood ratio and negative likelihood ratio of CA199,CA242 and CEA were calculated and analyzed. Results: CA19-9,CA242 and CEA in patients with malignant obstructive jaundice were significantly higher than those in patients with benign obstructive jaundice (P < 0.01). The AUC of CA19-9,CA242 and CEA were 0.882,0.904 and 0.843,respectively. The positive likelihood ratio priority of CA19-9,CA242 and CEA were 1.96,6.04 and 10.44,respectively,and the negative likelihood ratio priority was 0.11,0.30 and 0.42,respectively. Serial combination testing increased the diagnostic specificity,and parallel combination testing increased the diagnostic sensitivity. Conclusions: Combined measurement of serum CA19-9,CA242 and CEA is valuable in differential diagnosis of benign and malignant obstructive jaundice.