Intestinal ischemia includes all the conditions in which the blood supply to the gastrointestinal tract is not adequate to its metabolic demand. Several ischemic intestinal disorders differ in clinical presentation (acute versus chronic), etiology (occlusive versus nonocclusive), pathophysiology (arterial or venous), severity (mucosal versus transmural necrosis), and location (small bowel versus large bowel). Atherosclerosis, thromboembolic disease, hypoperfusion states, and hypercoagulable disorders are the most common causes. Reperfusion, oxygen-derived free radicals, and eicosanoids contribute to the pathogenesis of bowel injury and the systemic response that occur after ischemia. The diagnosis and treatment of intestinal ischemia are still challenging despite the advances of radiology, intensive care, and surgery. This article reviews the latest data about etiology and pathophysiology of bowel ischemia to explain the bases of diagnosis and treatment of this condition.