Postoperative hemorrhage is one of the most severe complications after pancreatic surgery. Due to the lack of an internationally accepted, universal definition of postpancreatectomy hemorrhage (PPH), the incidences reported in the literature vary considerably, even in reports from randomized controlled trials. Because of these variations in the definition of what constitutes a PPH, the incidences of its occurrence are not comparable. The International Study Group of Pancreatic Surgery (ISGPS) developed an objective, generally applicable definition of PPH based on a literature review and consensus clinical experience. Postpancreatectomy hemorrhage is defined by 3 parameters: onset, location, and severity. The onset is either early ( 24 hours). The location is either intraluminal or extraluminal. The severity of bleeding may be either mild or severe. Three different grades of PPH (grades A, B, and C) are defined according to the time of onset, site of bleeding, severity, and clinical impact. An objective, universally accepted definition and clinical grading of PPH is important for the appropriate management and use of interventions in PPH. Such a definition also would allow comparisons of results from future clinical trials. Such standardized definitions are necessary to compare, in a nonpartisan manner, the outcomes of studies and the evaluation of novel operative treatment modalities in pancreatic surgery.