Superior mesenteric venous (SMV) thrombosis is an uncommon cause of mesenteric ischemia, frequently presenting with nonspecific and subacute symptoms. We report a case of a 28-yr-old man presenting with symptoms and radiographic changes suggestive of Crohn's disease who, upon further evaluation, was found to have SMV thrombosis. A search for a precipitating condition revealed a strong family history of thromboembolic disease and deficiency of protein C. The patient responded to supportive therapy and anticoagulation.