Spontaneous dissection of the superior mesenteric artery is an unusual cause of mesenteric ischemia. Diagnosis can be based on findings of the helicoidal computed tomography or selective angiography of the superior mesenteric artery. We report two male patients, aged 47 and 50 years, who were admitted for abdominal pain. Isolated superior mesenteric artery dissection was confirmed by angiography. Both patients were treated with anticoagulation, conservative measures and recovered uneventfully (Rev Méd Chile 2002; 130: 1282-8).