Introduction. Cerebral venous sinus thrombosis (CVST) is a rare form of cerebrovascular disease, which may manifest clinically by a wide variety of signs and symptoms. It has been associated with multiple risk factors including genetic or acquired blood disorders, infections, and trauma. Case Report. Man of 17 years who presented with 10 days of intense global headache with nausea and vomiting and subsequent onset of mild hemiparesis and hypoesthesia in right hemibody. Studies show venous thrombosis of the superior longitudinal sinus. It was identified a gene mutation in prothrombin G20210A as a probable cause of the thrombosis. Conclusions. Substitution of guanine for adenine at nucleotide 20210 in the coding region of the prothrombin gene is the second most common primary thrombophilia. Multiple cases of CVST have been associated with this mutation. In the presence of CVST must be considered the primary studies for thrombophilia gene mutations, including prothrombin G20210A.