The first publication on Lemierre Syndrome appears in 1936 by Lemierre. It is defined as an ?oropharynx bacterial infection characterized by the thrombophlebitis in the internal jugular vein, derived in a systemic septic embolism?. In 81% of the cases, the Fusobacterium necrophorum is the most frequent etiologic agent. Fever is the most common symptom, but it can depending on the primary infection, tonsillitis, mastoiditis or odontogenic infection. According to the literature the mortality is very low, but with a significant morbidity, that is why the diagnosis and early treatment is very important. The diagnosis it´s clinical, even though the CT scan and other diagnosis methods (echography, MRI) help to determine the extent of the infection. It?s necessary to administrate the antibiotics endovenous at high dose, (keeping in mind that the most frequent micro organism is anaerobic), and vital support measures if neccessary. We present a case report of Lemierre Syndrome associated to an odonthogenic infection caused by the 4.8 molar.