Background: The mild acute pancreatitis is a self-limiting disease that ranges about 80–90% of patients with only minimal or transitional systemic manifestations, but about 20–30% of patients develop a severe disease that can progress to systemic inflammation and cause pancreatic necrosis, multi-organ failure, and potentially death. Objective: To assess predictive outcome of Acute Pancreatitis based on RDW value. Methods: About 123,patients were recorded and observed ,who are diagnosed as acute pancreatitis at the time of admission in surgical department at Karnataka institute of medical science hubballi, karnataka. Result: The number of people who are diagnosed acute pancreatitis are more in the age group 30-39 yrs by about 34.2% (around 44 patients) among 123 total acute pancreatitis patients. The distribution of acute pancreatitis is more in males in the age group 20-29 years. Among 123 patients (91.1%) of the acute pancreatitis have alcoholic history. 15 patients (12.2%) of the acute pancreatitis was found to have increased RDW. 45 patients (97.8%) of the acute pancreatitis were discharged was found to have increased RDW. Around 2.2% patients had death was found to have increased RDW. Conclusion: RDW being a simple parameter which is easily available in a simple routine CBC thus, can be used as a novel predictor of acute pancreatitis. It is a cost effective measure for predicting acute pancreatitis prognostic value