Objective To compare biliary stent versus combined biliary stent with intracavitary irradiation using 125I seed implantation to treat patients with malignant obstructive jaundice.Methods 62 patients with malignant obstructive jaundice after drainage with PTCD were randomized into two groups:Group A:biliary stent combined with 125I seed implantation (the treatment group),Group B:biliary stent alone (the control group).Postoperative change in jaundice,tumor recurrence,T lymphocyte subsets and survival time were compared between these two groups.Results The change in total serum bilirubin in the two groups of patients showed no significant difference at postoperative 1 month (P ＞ 0.05).However,Group A was better than Group B (P ＜ 0.05) at postoperative I month and 3 months.On follow-up,one patient developed recurrent biliary obstruction in Group A and 12 patients in Group B (P ＜ 0.05).When compared with the preoperative values,CD4 and the ratio of CD4/CD8 increased significantly in Group A at 1 to 2weeks postoperative (P ＜ 0.05),and there was no difference in CD3 (P ＞ 0.05).For patients in Group B,there were no significant difference in CD3,CD4 and CD4/CD8 ratio at 1 ～ 2 weeks postoperative when compared with the preoperative values (P ＞ 0.05).The median survival time for Group A was 10.9 months and for Group B 7.1 months (P ＜ 0.05).Conclusions Intracavitary irradiation using 125I seed implantation combined with biliary stent was better than stenting alone in the treatment of malignant obstructive jaundice.The combined treatment better relieved jaundice,improved immune function and prolonged survival time.