Acute pancreatitis (AP) is one of the most common acute surgical diseases of the abdominal organs. In 1992 at the International Symposium the classification of AP was established in Atlanta (USA). Over time new knowledge and experience required adjustment in the classification of Atlanta-92. In 2011, an updated classification of AP was presented at the Congress of Pancreatologists in Cochin (India). The severity of AP is determined by local and systemic criteria. Local criteria are sterile or infected Pancreas necrosis . Transient or chronic multiple organ failure belong to Systemic criteria. Acute Pancreatitis severity are divided into mild, moderate and severe types. There are early (1-st week) and late (>1 week) clinical phases of AP. Morphological forms of Apare divided into edematous and necrotic pancreatitis (sterile or infected). Computed tomography (CT) imaging plays an important role in diagnosis and staging of acute pancreatitishas. Local complications of AP are divided into four types, depending on the presence of pancreatic necrosis and the time elapsed since the onset of pancreatitis. With edematous pancreatitis, an acute accumulation of peripancreatic (unencapsulated) fluid formed in the first 4 weeks. A pseudocyst (encapsulated) forms after 4 weeks. With necrotic pancreatitis, acute necrotic congestion (forms in the first 4 weeks), limited necrosis (encapsulated) forms after 4 weeks. Based on these data, the radiologist becomes one of the key members of the multidisciplinary team for the diagnosis and treatment of AP. The principles of treatment methods of AP are established. With mild-edematous pancreatitis, a conservative approach is used. In severely infected pancreatic necrosis, the general principle remains: repeated revisions, sanations, removal of necrotic foci. Thus, the accuracy of prognosis of pancreatic necrosis can be improved while using clinical, laboratory and instrumental data. Nowadays, a single classification of AP has been created, a big step has been taken in the diagnosis of pancreatic necrosis. Methods of the treatment and prevention of complications of AP have been identified, although there is no yet full consensus on these issues and established recommendations.