Acute pancreatitis (AP) is an inflammatory disease of highly variable severity, ranging from mild cases with low mortality to severe cases with high mortality. Numerous biomarkers have been studied as potential early predictors of the severity of this disease so that treatment can be optimally tailored to prevent complications. We aim to present and discuss the most relevant biomarkers for early severity assessment in AP that have been studied to date. We review the current literature on biomarkers that have been used to predict the severity in AP. C-reactive protein (CRP) is still considered to be the gold standard, with a cut-off value of 150 mg/ml 48 h after disease onset. Other markers, including procalcitonin (PCT) and interleukin 6 (IL-6) have been implemented in some hospitals, but are not used on a routine basis. Most other markers, including acute phase proteins (LBP, SAA, PTX3), cytokines (Il-8, TNF-a, MIF), activation peptides of pancreatic proteases (TAP, CAPAP, PLAP), antiproteases (AAT, a2M), adhesion molecules (ICAM-1, selectins, E-cadherin) and leukocyte-derived enzymes (PA2, PMN-E) have shown some promising results but have not been routinely implemented. Furthermore, new and interesting biomarkers (Copeptin, TRX-1, Ang-2, E-2) have shown good results, but more research is needed to determine if they could play a role in the future. Various reasons why new markers for disease severity have not been adopted in daily routine include low accuracy, cumbersome laboratory techniques and high cost. Despite these difficulties, research is still very active in finding new markers to predict the severity of AP.