Thromboembolic events are an infrequent complication of hormonal treatment for infertility and are generally related to the ovarian hyperstimulation syndrome. The presence of factor V Leiden and a mutation of G20210A prothrombin mutation are further risk factors for thromboembolic events. We describe a case of dual cerebral vein thrombosis in a woman with prothrombin mutation homozygosity and ovarian hyperstimulation syndrome.