Intraabdominal bleeding, the most life-threatening complication following pancreaticoduodenectomy (PD), most often is associated with failure of a pancreaticojejunostomy anastomosis or with intraabdominal infection. We investigated whether placement of an omental flap around the splanchnic vessels in PD could reduce the occurrence of intraabdominal bleeding and other postoperative complications. One hundred consecutive patients who underwent PD at the authors' institution between January 2000 and October 2004 were enrolled in this prospective study. After dissection of the hepatoduodenal ligament, the major splanchnic arteries and the portal vein were covered by the omental flap. Preoperative condition, incidence of pancreatic fistula, intra-abdominal bleeding, other complications, treatment mortality, and hospital stay were analyzed for interrelationships. The frequency of pancreatic fistula (20%) differed little from those in previous reports. However, intraabdominal bleeding was observed in only 1 (1.0%) patient, who was considered to have too thin a flap. No intraabdominal abscess was encountered. No mortality or complications occurred in relation to the omental flap. Thus, wrapping an omental flap around dissected splanchnic vessels in PD reduced postoperative intraabdominal bleeding and infection, but failed to prevent pancreatic fistulas.