As already reported, PGE1 induces a valid erection, when administered intracavernously, without causing prolonged erection or general side effects. We have tested PGE1 (< 20 micrograms) in 180 patients suffering from organic erectile impotence, a complete erection was observed in 130 (72.2%), while incomplete erection was noted in 37 (20.5%). In both groups (92.7%) erection was sufficient for sexual intercourse. Among the best results, 41 patients had previously received high doses intracavernous injection of papaverine, without any benefit, and 15 patients have cavernosal venous leakage documented by cavernosometry and cavernosography before prostaglandin E1 test. Tumescence without rigidity was noted in 13 (7.2%). Of these 167 patients, 95 entered an autoinjection protocol for treatment of erectile dysfunction, using special device. In our series neither systemic reaction nor prolonged erection occurred. No fibrosis of cavernous tissue or scar formation was observed after up to 125 injections. However, 19 patients (10.5%) reported burning sensations during the entire period of erection and one patient (0.5%) had an haematoma at the site of the injection. PGE1 is effective in inducing artificial penile erection and it has a role in the diagnosis and treatment of erectile dysfunction, it is considered to be a more suitable agent than other vasoactive drugs.