Background: Indications for preoperative biliary drainage (PBD) in the context of hepatectomy for hilar malignancies are still debated. The aim of this study was to investigate current European practice regarding biliary drainage before hepatectomy for Klatskin tumours. Methods:This was a retrospective analysis of all patients who underwent formal or extended right or left hepatectomy for hilar cholangiocarcinoma between 1997 and 2008 at 11 European teaching hospitals, and for whom details of serum bilirubin levels at admission and at the time of surgery were available. PBD was performed at the physicians' discretion. The primary outcome was 90-day mortality. Secondary outcomes were morbidity and cause of death. The association of PBD and of preoperative serum bilirubin levels with postoperative mortality was assessed by logistic regression, in the entire population as well as separately in the right- and left-sided hepatectomy groups, and was adjusted for confounding factors. Results: A total of 366 patients were enrolled; PBD was performed in 180 patients. The overall mortality rate was 10�7 per cent and was higher after right- than left-sided hepatectomy (14�7 versus 6�6 per cent; adjusted odds ratio (OR) 3�16, 95 per cent confidence interval 1�50 to 6�65; P = 0�001). PBD did not affect overall postoperative mortality, but was associated with a decreased mortality rate after right hepatectomy (adjusted OR 0�29, 0�11 to 0�77; P = 0�013) and an increased mortality rate after left hepatectomy (adjusted OR 4�06, 1�01 to 16�30; P = 0�035). A preoperative serum bilirubin level greater than 50 �mol/l was also associated with increased mortality, but only after right hepatectomy (adjusted OR 7�02, 1�73 to 28�52; P = 0�002). Conclusion: PBD does not affect overall mortality in jaundiced patients with hilar cholangiocarcinoma, but there may be a difference between patients undergoing right-sided versus left-sided hepatectomy.