Pancreatitis is a diffuse systemic immuno-inflammatory response to a localized process of auto-digestion within the pancreatic gland, caused by premature activation of proteolytic digestive enzymes. According to the ATLANTA criteria (1992) we recognized a mild and a severe acute pancreatitis (SAP ) . Mortality rate in SAP account up to the 20 percent and most complications and deaths are due to an inflammatory immune response to pancreatic necrosis and/or infection. Patients affected by SAP rapidly incur accelerated catabolism and thus nutritional support is essential, especially in the earliest period of the disease. Recent observations show that the route of nutritional support may also affect disease severity and its course. In this view several important questions about nutritional support need to be addressed : indication , timing, enteral vs parenteral and composition . With this review we analyze the state-of-the-art and we present a decisional flow chart to better manage the nutritional support in SAP.