Severe acute pancreatitis is morphologically characterized by an extensive and prolonged pancreatic and retroperitoneal inflammation with surimposed patchy or generalized areas of necrosis and hemorraghe in the pancreas and surrounding tissues. Clinical hallmarks include the early development of remote organ dysfunctions, notably cardiorespiratory failure and the late emergence of local complications (hemorraghe, acute pseudocyst and, most importantly, infection). The severity of the attack and the outcome of the patient are critically dependent on the presence and the extent of regional necrosis and are closely related to the casual bacterial contamination of these devitalized areas. The early identification of severe episodes is of therapeutic interest. This prognostic staging is best achieved with a combination of a set of clinical and laboratory data, initial CT findings and single biochemical indicators. Sequential assessment of severity, using biochemical markers and morphological data, is mandatory in order to monitor the fate of regional necrosis. Intensive care treatment includes supportive care of distant organ failures, prophylactic antibiotics and nutritional support.