Background: Mesenteric vein thrombosis (MVT) is uncommon and accounts for 5-10% of all mesenteric ischemic events. In 80% of cases, an etiologic factor is found. The clinical presentation varies and the diagnosis is made based on imaging studies. The treatment involves anticoagulation alone or in combination with surgery. Aim: To describe the clinical characteristics of patients with MVT. Patients and methods: Retrospective and prospective review of all cases with MVT, treated between 1995-2001. The clinical presentation, imaging studies, treatment and outcome were evaluated. Results: 29 cases of MVT were reviewed (14 females, age 56 ± 15 years). Twenty two patients (76%) had recognizable risk factors. The main symptoms were abdomianl pain (86%) and vomiting (55%). The diagnosis of acute mesenteric ischemia was suspected on admission only in 6 patients (21%). Thirteen patients underwent transabdominal color Doppler ultrasonography and the diagnosis was confirmed for 11 of these (85%). Twenty out of 24 patients (85%) studied with computed tomography, had positive signs of MVT. Twenty one patients (72%) recieved anticoagulation, 10 of whom also underwent surgery. Four patients (14%) received surgical treatment alone. Four patients were not treated. Seven patients (24%) died. Conclusions: MVT is difficult to identify. It is necessary to have a high degree of suspicion in patients who have risk factors. The diagnosis is made with imaging studies. The treatment consists of early anticoagulation and surgical intervention when indicated.