Six patients with dissection of the superior mesenteric artery (SMA) who were treated at our hospital between 1993 and 1999 were studied. Hypertension was considered significant as a risk factor. The clinical features were characterized by severe abdominal pain which radiated posteriorly, back pain, weak bowel sounds and exacerbation by eating. An ultrasonographic examination and a computed tomographic scan of the abdomen were useful for diagnosis. Four cases showed full recovery under conservative management with anticoagulant or antiplatelet drugs. Two cases without recovery should be considered intervention if they have progressive courses. This disease should be kept in mind on differential diagnosis of abdominal pain, because it may be overlooked without a correct diagnosis.