Abstract： AIM:To evaluate the diagnostic value of combined detection of serum GGT, GGT/ALP ratio and CA19-9 in patients with malignant obstructive jaundice. METHODS:A total of 366 patients diagnosed as obstructive jaundice in our hospital from July 2002 to July 2007 were included in this retrospective study. All the study objects were divided into 3 groups according to the clinical diagnosis:Neoplastic obstructive jaundice group, biliary calculi with inflammation obstructive jaundice group and biliary calculi without inflammation obstructive jaundice group. Forty healthy volunteers were recognized as control group. Serum CA19-9 levels was determined by radioimmunoassay, srum GGT and ALP levels were determined by absorption spectrometry.RESULTS:There are significant differences in the levels of GGT, GGT/ALP and CA19-9 between control group and the obstructive jaundice groups(P < 0.05); In the obstructive jaundice groups the levels of GGT and CA19-9 were significantly higher in neoplastic obstructive jaundice group than the biliary calculi obstructive jaundice groups(P < 0.05), but the levels of GGT/ ALP were significantly lower in neoplastic obstructive jaundice group(P < 0.05); the levels of GGT were significantly higher in biliary calculi with inflammation obstructive jaundice group than biliary calculi without inflammation obstructive jaundice group (P < 0.05), but no significant differences in the levels of GGT/ALP and CA19-9 were found between the two groups(P >0.05).The diagnosis rates of neoplastic obstructive jaundice using GGT,CA19-9 and the combined detection were 81.56%, 72.63% and 92.74%, respectively. The diagnosis rates of combined detection were significantly higher than using GGT or CA19-9 separately (P<0. 05). CONCLUSION:The detection of GGT, GGT/ALP and CA19-9 can assist the identification of benign and malignant obstructive jaundice. The combined detection can improve the diagnosis rate of neoplastic obstructive jaundice.