Mesenteric ischemia is an important clinical condition becoming more prevalent with aging of the population. Mesenteric ischemia may be manifest in an acute presentation, usually secondary to thromboembolism or cardiac insufficiency. Patients have abdominal pain, lactic acidosis, benign abdominal examination, and, often, coexistent multisystem organ dysfunction. Chronic mesenteric ischemia is secondary to proximal arterial stenosis or occlusions inadequately compensated by collateral flow. Clinical presentation may simulate occult malignancy. In this review article, the role of Doppler sonography and other diagnostic imaging tests in suspected acute mesenteric ischemia and mesenteric arterial insufficiency are evaluated with emphasis on diagnostic criteria and appropriate use in each clinical context.