The cause of the reduction in mortality from acute pancreatitis is improved diagnosis. Although not completely specific markers, amylase and lipase still play an irreplaceable role in establishing the diagnosis. A threefold increase in their levels is considered pathognomic. Determination of other enzymes has not found general acceptance mainly because of the costs involved. Severity of the condition is assessed using laboratory investigations and imaging methods. The best characterized is C-reactive protein, its drawbacks include a low specificity and its slowly rising levels, peaking on days 3 – 4. Among imaging methods, ultrasound has been employed to rule out biliary etiology and to assess local complications, while CT with a contrast-medium bolus will reliably visualize pancreatic necrosis and has become standard procedure. Magnetic resonance imaging may play a similar role in the future.