Diagnostic imaging in patients with suspected acute mesenteric ischemia is started with abdominal ultrasound including duplex sonography of the mesenteric vessels. Despite low sensitivity even in experienced hands, ultrasound is used because operative treatment can be initiated without further imaging if a positive diagnosis is made. Plain abdominal X-rays are usually unspecific in acute mesenteric ischemia and are mainly used to rule out differential diagnoses. Spiral CT (ideally using a multislice technique) can accurately demonstrate morphology of the arterial and venous mesenteric vessels, changes in the bowel wall, and additional mesenteric or peritoneal findings. Therefore, CT has the potential for diagnosis of mesenteric ischemia on a pathological basis. Furthermore, CT is successfully used to confirm or exclude most other causes of acute abdominal conditions. Magnetic resonance imaging (MRI) may be as accurate as CT for the diagnosis of acute mesenteric ischemia and its differential diagnoses. However, MRI is not widely available and therefore not used as an emergency imaging modality so far. Catheter angiography remains the diagnostic gold standard for mesenteric vasculature when spiral CT is not available.