Until Atlanta Classification (AC) made in 1992, there was not any classification of acute pancreatitis (AP). Last twenty years AC let us compare results and papers. But the increasing understanding of the pathophysiology of AP, improvements in diagnostic methods and the development of minimally invasive tools for radiological, endoscopic and surgical management of local complications, several authors have called for the AC to be reviewed. Last months, two new classifications of AP have been published. We made a historical review of AC, the two new classifications and a comparison between them.