The most common cause of occlusive mesenteric artery disease is ostial atherosclerosis. Non-atherosclerotic causes account for 5-10 % of all cases of chronic mesenteric ischemia (CMI). The vasculitides consist in a varied group of conditions characterized by an infl ammatory response of vessel wall, with or without associated necrosis and granulomas, affecting 20 individuals per million a year. These diseases have different etiologies and pathogenic mechanisms, albeit most of them are not completely understood. Chronic infl ammation can weaken the media and thin the arterial wall leading to aneurysm, or it can cause thickening of the arterial wall, resulting in stenosis and occlusions [ 1 -4 ].Although mesenteric manifestations of vasculitides are considered rare, accounting for less than fi ve percent of all cases of mesenteric ischemia [ 1 ], reports have suggested that gastrointestinal (GI) manifestations of vasculitis are isolated and can be the fi rst manifestation of this group of diseases in up to 13-16 % of cases. In addition, the clinical manifestations may be fatal and require early diagnosis and immediate management [ 3 , 4 ]. This chapter presents the clinical features and approaches to diagnosis and treatment of non-atherosclerotic causes of mesenteric ischemia, including mesenteric vasculitis (MV), neurofi bromatosis, and mid-aortic syndrome. Other causes such as median arcuate ligament compression syndrome are not discussed. Specifi c vasculitis disorder details such as American College of Rheumatology diagnostic criteria and treatment were not in our scope and will not be discussed.