First differentiated from arterial causes of acute mesenteric ischemia 75 years ago, acute mesenteric venous thrombosis (MVT) is an uncommon disorder with non-specific signs and symptoms, the diagnosis of which requires a high index of suspicion. The location, extent, and rapidity of thrombus formation determine whether intestinal infarction ensues. Etiologies, when identified, usually can be separated into local intra-abdominal factors and inherited or acquired hypercoagulable states. The diagnosis is most often made by contrast-enhanced computed tomography, though angiography and exploratory surgery still have important diagnostic as well as therapeutic roles. Anticoagulation prevents clot propagation and is associated with decreased recurrence and mortality. Thrombectomy and thrombolysis may preserve questionably viable bowel and should be considered under certain circumstances. Evidence of infarction mandates surgery and resection whenever feasible. Although its mortality rate has fallen over time, acute MVT remains a life-threatening condition requiring rapid diagnosis and aggressive management. Chronic MVT may manifest with complications of portal hypertension or may be diagnosed incidentally by noninvasive imaging. Management of chronic MVT is directed against variceal hemorrhage and includes anticoagulation when appropriate; mortality is largely dependent on the underlying risk factor.