Various definitions and classification systems of acute and chronic pancreatitis have been elaborated in the past 3 decades and are critically reviewed in this article. According to these classifications acute pancreatitis is characterized by complete recovery, whereas chronic pancreatitis implies irreversible morphological and functional changes, which usually can only be proven in an already advanced disease state. Acute and chronic pancreatitis so far represents two different disease entities. The classifications have no word for the chronic inflammatory process that ultimately leads to pancreatic destruction, but does not yet yield abnormal imaging procedures and function tests. More interdisciplinary research in early chronic pancreatitis is needed to better understand its pathophysiology.