Thirty-six clinical and laboratory parameters in 770 consecutive patients undergoing biliary tract surgery over a 3 year period were analyzed in an effort to define the patients at greatest risk. Twelve parameters had a significant correlation with hospital mortality, while multivariate analysis revealed that septic shock, malignant obstruction, serum albumin less than 3.0 gm%, history of hypertension, and plasma urea nitrogen greater than 20 mg% had an independent significance in predicting postoperative mortality. The presence of more than 2 of these risk factors identified a group of patients with an 18% mortality rate. It is for this group of patients that adequate pre-operative preparation such as fluid resuscitation, prophylactic antibiotics, and nutritional support are essential. The controversial preoperative biliary drainage might be only indicated in this group of patients.