Objective:To study the effect of first drainage failure on the prognosis of perihilar cholangiocarcinoma (PHCC).Methods:The clinical data of 68 patients with PHCC undergoing surgery in the Department of Pancreatic and Metabolic Surgery of Nanjing Drum Tower Hospital, Affiliated to the Medical School of Nanjing University, from April 2014 to December 2022 were retrospectively analyzed, including 46 males and 22 females, aged (63±9) (range, 39-80) years old. The patients were divided into two groups based on whether the first drainage was successful: successful group ( n=34) and failed group ( n=34). The patient's age, gender, first drainage, complications and other clinical data were collected. Patients were followed up by outpatient or telephone review. Kaplan-Meier method was used for survival analysis, and log-rank test was used for survival comparison. Results:Compared to the successful group, the drainage time [41(28, 52) d vs. 20(14, 28) d], the drainage tube adjustment rate [32.4%(11/34) vs. 0(0/34)], and the incidence of complications after drainage [88.2% (30/34) vs. 0(0/34)] were all increased in the failed group, with the adjustment rate of drainage position decreased [82.4%(28/34) vs. 100%(34/34)] (all P<0.05). Compared to the successful group, the incidence of abdominal infection was higher [70.6%(24/34) vs. 44.1%(15/34)] in the failed group ( P=0.027). The 5-year cumulative survival rates of the failed group and the successful group were 61.4% and 44.1%, respectively ( P>0.05). Conclusion:Compared to the patients of PHCC with first successful drainage, the risk of abdominal infection is increased when first drainage failed, while the incidence of postoperative complications, in-hospital mortality and long-term survival rate are comparable.