Benign idiopathic intracranial hypertension (BIH) in association with prothrombotic conditions has been reported with increasing frequency in the medical literature. Recently, activated protein C resistance (APCR) has been identified as a factor in some cases. Because of its high prevalence, factor V Leiden mutation (FVL) is the most frequent coagulation abnormality associated with cerebral venous thrombosis. Reduced craniospinal fluid reabsorption due to damaged arachnoid villi secondary to microthrombus formation has been proposed as an explanation for the physiopathology of BIH and FVL. We describe two patients with a diagnosis of BIH, in whom the only risk factor was heterozygosity for FVL mutation.