Cerebral venous thrombosis (CVT) is mostly caused by pro-thrombotic factors. Hyperthyroidism is not a wellknown risk factor. We present a case report on a 17 year old girl who developed life-threatening CVT after Graves’ disease. A review of the literature reveals further 34 cases of CVT and hyperthyroidism. Abnormalities in the coagulation system leading to hypercoagulability such as increased coagulation factors are detected in patients with hyperthyroidism, and these abnormalities seem to be thyroxin-dependent.