Acute pancreatitis is the most frequent gastrointestinal cause of hospitalization. The prognosis of AP depends on its severity, which was classified as mild, moderate, or severe by the latest revised Atlanta classification. Most patients present with mild or moderate AP, and only 15–20% of patients have severe AP. Severe episodes may involve a progression to extensive pancreatic necrosis, development of the systemic inflammatory response syndrome (SIRS), multi organ failure, rapid clinical deterioration, and even death. The mechanism of injury in pancreatitis is the premature activation of enzymes, leading to auto digestion. Any injury to the acinar cell impairs the secretion of zymogen granules or damages the duct epithelium and thus delays enzymatic secretion, can trigger acute pancreatitis. Once cellular injury has been initiated the inflammatory process can lead to pancreatic edema, hemorrhage and eventually necrosis. As inflammatory mediators are released into circulation Systemic complication can arise, such as hemodynamic instability, bacteremia, Acute Respiratory Distress Syndrome, pleural effusions, gastrointestinal hemorrhage, renal failure and DIC. Acute pancreatitis may be categorized as mild or severe. Mild acute pancreatitis is characterized by the interstitial edema of the gland and minimal organ dysfunction. 80% of the patients will have mild attack of pancreatitis (Mortality-around 1%). Severe acute pancreatitis is characterized by pancreatic necrosis, a severe systemic inflammatory response and often multiorgan failure (Mortality-varies from 20-50%). About one third of deaths occur in the early phase of the attack, from multiorganfailure, while deaths occurring after 1st week are due to septic complications. Most patients of acute pancreatitis recover without complications, the overall mortality rate of this illness is between 2-5%. The most common cause of acute pancreatitis is gallstones worldwide. The Bedside Index for Severity in Acute Pancreatitis (BISAP) score has been developed to identify patients at high risk for mortality or severe disease early during the course of acute pancreatitis. Majority of the scoring systems like Modified Glasgow Score and Ranson’s Criteria require diverse biochemical parameters, which are limited in the hospital settings in developing countries like India. Moreover early therapeutic window is missed in these scoring systems, as they are assessed after 48 hours. The APACHE II scoring system also requires collection of large number of parameters. To overcome the above limitations, a simple and accurate clinical scoring system, theBISAP –Bedside Index for Severity in Acute Pancreatitis was introduced. The scoring system conveniently stratifies the patients according to the risk of mortality, and identifies the patients at increased risk of mortality early in the therapeutic window, thus enabling effective future management. BISAP Score: It includes the following parameters, 1.Blood urea nitrogen >25 mg/dl. 2.Impaired mental status (Glasgow coma score <15). 3.Systemic inflammatory response syndrome (SIRS). SIRS is defined as presence of two or more of the following criteria: a. Pulse >90bpm, b. Respiratory rate >20/min or PaCO2<32mmhg, c. Temperature >38 or <360C, d. WBC count >12000 or <4000 cells/mm3 or >10% immature bands 4.Age > 60 years. 5.Pleural effusion, detected on imaging (chest X-ray or USG or CT scan Each point on BISA Pscore is worth one point within 24 hours of presentation. There is steady increase in the risk for mortality with the increasing number of points. BISAP score is an uncomplicated, quick and reasonably reliable method for assessment of disease severity on admission. A score of ≥3 indicates a severe acute pancreatitis. Discussion: Prediction of Severity of Acute Pancreatitis is important in order to decrease morbidity and hospital stays. Many scoring systems have been developed to determine the severity of acute pancreatitis early so that better care can be provided to patients. An ideal scoring system should be simple, safe, cheap and less time consuming. BISAP score is one of the scoring systems to predict the severity of acute pancreatitis. It has got 5 variable that can be done quickly in Emergency ward within 24 hours