BACKGROUND: Varicose vein surgery is very commonly performed. Also, it is very frequently employed for recurrent disease. The recognition of the normal or variant veins, inducing incompetency, is a prerequisite for effective treatment. The thigh extension of the small saphenous vein, the so-called Giacomini vein, was extensively described in 1873 by Carlo Giacomini in an incidence of 72%. However, such a vein is usually underestimated in classic surgical textbooks.DESCRIPTION OF CASES: We present two cases of Giacomini vein found in two cadavers, dissected for academic purposes in the Department of Anatomy, where the small saphenous vein displayed a thigh extension without terminating into the popliteal vein. In one case Giacomini vein drained into the large saphenous vein, while in the other case the vein divided into two branches, separately draining into the large saphenous vein and the subcutaneous tissue of the gluteal region.CONCLUSION: Due to the fact that Giacomini vein could be incompetent, associated with or without varicose saphenous vein trunks, the vascular surgeon should keep in mind that anatomical entity, to include it in preoperative ultrasound scanning control. Moreover, this vein could be utilized as an autologous graft, when the large saphenous is not available. Hippokratia 2015; 19 (3): 263-265.