Severe acute pancreatitis leads to a dramatic fluid loss in the intraperitoneal space which may result in circulatory decompensation. Sequestration of fluid can amount up to 40 percent of the circulating blood volume. The amount of fluid and electrolyte replacement is often misjudged leading to a higher rate of complications and a higher mortality rate of the disease. Furthermore, subsequent and adequate fluid resuscitation seems to influence the prognostic course of the disease by improving the perfusion and oxygenation of the pancreas. Otherwise volume overload may cause cardiopulmonary decompensation in the case of synchronous cardiopulmonary comorbidities. Therefore, an important part of treatment relies on careful haemodynamic monitoring, if necessary managed in an intensive care unit. Usually most patients with acute pancreatitis will be treated on a non-intensive medical ward which allows a differentiated and continuous haemodynamic monitoring only to a limited extent. Apart from monitoring circulatory parameters and measuring central venous pressure, there are other clinical methods, laboratory tests and radiological diagnostic procedures to determine the amount of intravascular fluid deficit and the individual volume demand of patients with acute pancreatitis. Prospective clinical trials for evaluation of pancreatitis-specific volume management do not exist so far. The aim of this review is to provide background information on invasive and non-invasive diagnostic methods for detection of circulatory hypovolemia in acute pancreatitis.