The incidence and prevalence of acute pancreatitis (AP) is increasing over time. The diagnosis of acute pancreatitis is established by revised Atlanta criteria (2012). Multiple criteria and scoring systems have been used for assessment of severity of AP. Majority of acute pancreatitis cases (80%) are mild, the challenge remains in early diagnosis, severity assessment and treatment of severe AP and its complications. Assessment of severity of AP is important part of management because line of treatment depends on aetiology and severity of acute pancreatitis. In this article a comprehensive review of recent advances in diagnosis and severity assessment of acute pancreatitis has been described.