Malrotation can be difficult to diagnose after the newborn period because of intermittent symptoms and vague clinical findings, but malrotation with midgut volvulus is usually quite striking in its presentation. Early diagnosis and surgical treatment are essential to prevent acute ischemic infarction of the bowel, although chronic complications are rare. The authors present an unusual case of mesenteric venous thrombosis secondary to chronic midgut volvulus. A 13-year-old girl presented with an 11-year history of recurrent bouts of abdominal pain evaluated at 3 other institutions without a diagnosis. At the referring hospital, an episode of bilious emesis associated with abdominal pain prompted a computerized tomography scan of the abdomen. This showed a calcified thrombus within the superior mesenteric vein (SMV). At laparotomy, malrotation with chronic 270 degree volvulus was found with evidence of mesenteric venous hypertension. Segmental occlusion was documented on magnetic resonance angiography. SMV thrombosis is an unusual complication of malrotation with chronic midgut volvulus.