In 2005, the International Study Group of Pancreatic Fistula developed a definition and grading of postoperative pancreatic fistula that has been accepted universally. Eleven years later, because postoperative pancreatic fistula remains one of the most relevant and harmful complications of pancreatic operation, the International Study Group of Pancreatic Fistula classification has become the gold standard in defining postoperative pancreatic fistula in clinical practice. The aim of the present report is to verify the value of the International Study Group of Pancreatic Fistula definition and grading of postoperative pancreatic fistula and to update the International Study Group of Pancreatic Fistula classification in light of recent evidence that has emerged, as well as to address the lingering controversies about the original definition and grading of postoperative pancreatic fistula.