Intra-abdominal hypertension (IAH) and abdominal compartment syndrome (ACS) are conditions that commonly manifest in critically ill patients. They are associated with a multiplicity of pathophysiological disturbances. This study retrospectively reviewed literature relating to IAH and ACS published in the last two decades to consolidate an understanding of the epidemiology, etiology, pathophysiology, diagnosis and non-operative management of these conditions. Additionally, the authors of this study have recently conducted a large study on intra-abdominal pressures of consecutive catheterised patients admitted to the Intensive Care Unit (N.=403). A preliminary analysis of this study has also been included.