Superior mesenteric vein thrombosis (SMVT) is a rare condition, usually caused by infec-tions, intra-abdominal inflammatory diseases, portal hypertension, hypercoagulable states, or contraceptive therapy. Due to its vague symptomatology, SMVT is often diagnosed only after an abdominal contrast-enhanced computed tomography (CT) scan. In this article, we present a case of SMVT in a patient with a history of contraceptive drug use and a recent cytomegalovirus infection. A 36-year-old female was admitted to our department with the clinical symptoms of an acute appendicitis. The patient was a smoker and had been using hormonal contraceptives for over a year. Surgery was deemed the best course of action. Before the operation, blood tests showed a mild lymphocytosis and altered liver enzyme levels, while coagulation values were normal. A contrast-enhanced CT scan revealed a complete superior mesenteric vein thrombosis without signs of bowel ischemia. Anticoagulants were immediately administered. A thrombophilia panel did not highlight any noteworthy elements. Cytomegalovirus (CMV) tests resulted positive. Since CMV is a rare, but potentially significant cause or precipitating factor for thrombo-sis in immunocompetent hosts, all patients with an unexplained fever and seemingly spontaneous thrombosis should be screened for CMV infection.