The main cause of chronic gastrointestinal ischaemia is atherosclerosis. Stenotic lesions of the mesenteric circulation are relatively common, but lead to chronic ischaemic complaints due to collateral circulation in probably only 2-3 per 100,000 inhabitants per year. The classical presentation (post-prandial abdominal pain, weight loss, upper abdominal souffle) is present in a minority of patients only. Symptoms also occur after exercise. Gastric ulcers and diarrhoea are less frequent. Although patients with 2 and 3 vessel involvement (coeliac artery, superior mesenteric artery and inferior mesenteric artery) usually experience the most severe ischemic complaints, patients with single vessel involvement can also develop symptoms. In the diagnosis of cases with abdominal complaints, factors that aggravate or reduce the complaints anamnestically are the guideline for supplementary diagnostics. The more frequent causes of the symptoms are to be excluded first. Doppler-ultrasonography of the mesenteric vessels can detect most stenotic lesions accurately. To establish the diagnosis visceral angiography is needed. A new method of examination is magnetic resonance angiography (MRA). Another new method is tonometry during exercise: a PCO2 value in the lumen that is higher than that in the blood indicates ischaemia. Non-invasive treatment of chronic gastrointestinal ischaemia is aimed at reduction of the gastrointestinal metabolic workload by smaller meals, at suppression of acid secretion, at inhibition of the secretion of gastric acid and on risk factors for atherosclerosis.