Acute pancreatitis is an unpredictable disease with a range of clinical courses. It is one of the most common diseases of the gastrointestinal tract with increasing annual worldwide incidence. The main cause of the disease are gallstones and alcohol abuse. Mortality is 5–10% and can increase up to 40% in severe disease. The article describes the most widely used classification of acute pancreatitis – the revised Atlanta classification of 2012. Diagnostic considerations, new findings in pathophysiology and latest advances in therapy are also discussed.