Background: Acute pancreatitis (AP) is a potentially life-threatening common gastrointestinal disorder with increasing incidence around the globe. Although the majority of cases will take an uneventful, mild course, a fraction of patients is at risk of moderately severe or severe pancreatitis which is burdened with substantial morbidity and mortality. Early identification of patients at risk of a severe disease course and an adopted treatment strategy are crucial to avoid adverse outcomes. Summary: In this review we summarize the most recent concepts of severity grading in patients diagnosed with AP by adopting recommendations of current guidelines and discussing them in the context of the available literature. The severity of AP depends on the presence of local and/or systemic complications and organ failure. To predict the severity early in the disease course, host-specific factors (age, comorbidities, body mass index), clinical risk factors (biochemical and physiological parameters and scoring systems), as well as the response to initial therapy need to be considered and revisited in the short term. Depending on the individual risk and comorbidity the initial treatment can be guided, which will be discussed in the second part of this review. Key Message: Predicting the severity of AP and adapting the individual treatment strategy requires multidimensional risk assessment and close observation during the early phase of AP development.