As color Doppler ultrasonography evaluates penile arterial system functionally, it also reveals the anatomy of the penile arterial system. Anatomy of intrapenile arterial system has been evaluated in 54 patients suffering from erectile dysfunction between ages range of 20 to 57 (mean age: 39.15±18.52) by color Doppler ultrasonography. The eha§tdffl0§is between cavernosal arteries Shd also the anastomosis between dorsal artery and cavernosal artery are the most commonly seen variations. The existence and number of cavernosal perforating arteries from dorsal artery should be considered in planning by-pass surgery. Further studies should be done in order to evaluate the importance ef these anastomosis for a special type of Impotence.