A healthy 16-year-old boy was hospitalized for fever, septic condition and thrombosis of the left internal jugular vein: The diagnosis of Lemierre syndrome (LS) with positive blood culture for Fusobacterium necrophorum was formalized. He was treated with antibiotics and anticoagulant therapy with enoxaparin with complete recovery. Four weeks after discharge, the jugular vein ecodoppler showed complete resolution of the thrombosis. LS is characterized by thrombosis of the internal jugular vein and anaerobic bacteremia often caused by Fusobacterium necrophorum. It is a rare disease in the post-antibiotic era, but with an increase in cases over the last twenty years. LS should be suspected in young, healthy patients with persistent pharyngitis followed by sepsis, pneumonia or atypical laterocervical pain. The diagnosis is confirmed by the identification of jugular venous thrombosis and is further confirmed by the growth of anaerobic bacteria on blood culture. Prolonged antibiotic and anticoagulant therapies are the essential elements of treatment. However, anticoagulant therapy for internal venous thrombosis associated with LS remains a controversy.