Background: A preoperative biliary stent is commonly used after the initial evaluation of the patient with a periampullary mass. Objective: To evaluate the effect of a preoperative biliary stent on operative difficulty, postoperative complications, and length of hospital stay after a pancreatoduodenectomy. Design: A retrospective review of a prospectively collected consecutive series. Setting: The Memorial Sloan-Kettering Cancer Center's Surgical Service, New York, NY. Patients and Methods: Seventy-four patients underwent pancreatoduodenectomy between March 1, 1994, and February 15, 1996. Thirty-five did not receive a biliary stent, and 39 received a biliary stent prior to medical evaluation. We analyzed patient, nutritional, laboratory, and operating room factors. Univariate analysis was by Student t test, χ2 test, and Fisher exact test; multivariate analysis was by logistic regression. Significance was defined at P<.05. Main Outcome Measures: Operative time, amount of blood loss, complications, and length of hospital stay. Wound complications were defined as cellulitis, superficial infections, and deep infections. Intra-abdominal complications were defined as intra- abdominal abscesses and pancreatic or biliary fistula. Results: Groups were equivalent for tumor size, risk of comorbidity, time spent in the operating room, and amount of blood loss. There was 1 perioperative death. Patients with a stent had significantly lower bilirubin (P<.03) and aspartate aminotransferase (P<.04) levels and a significantly increased risk of nodal positivity (P<.05). The patients with a biliary stent had an increased risk of wound or abdominal complications on univariate (P<.003) and multivariate (P<.02) analysis and tended toward a prolonged hospital stay (P<.04, Wilcoxon signed rank test). Conclusions: A preoperative biliary stent was associated with an increased risk of wound or intraabdominal complications; a stent may prolong the length of hospital stay. However, length of time under anesthesia, amount of blood loss, and transfusion requirements were not altered. A biliary stent should be used with a high degree of selectivity in the management of patients with resectable periampullary masses.