Evidence has been arising suggesting that Botulinum toxin type A [BTX-A] injections can relax smooth muscles fibers in the treatment of obesity and Detrusor muscle over-activity, similar effect on cavernosal smooth muscles would help in the treatment of erectile dysfunction [ED] resistant to oral and intracavernous injection [ICI] therapy, thus it could be an alternative option for failed medical and other injectable therapy.. to compare safety, efficacy and durability of different doses of BTX-A [50 and 100 Unit] in the treatment of Vasculogenic Erectile Dysfunction after failure of other ICI therapy.. Forty-five patients with Vasculogenic erectile dysfunction who are failed treatment with non-surgical options were included at this study after elimination of all patients who are not matching eligible criteria or not complete the follow up program. The patients   were randomized into 3equal groups, each group include 15 patients. Group [I] injected with 100U BTX-A, group [II] injected with 50U BTX-A and Control group injected with normal saline. All groups underwent follow up at 2 weeks, 3 months and 6 months intervals after injection, for assessment of all subjective data as, IIEF-5 Questionnaire [SHIM score], Erection hardness score [EHS], Sexual encounter profile [SEP 2 and 3], Global assessment score[ GAS 2 and 3]. Also assessment of objective data by penile Doppler details.. Although 25 patients [55.6%] respond to BTX-A injection subjectively and objectively {13 patients [28.9%] in group [I] and 12 patients [26.7%] in group [II]}, but this impressive effect was not durable especially in group [II] as 9 patients [20%] show lost effect through complete follow up till 6 month in comparison to 5 patients [11.1%] in group [I] show same lost effect. Besides that, 5 patients [11.1 %] not responding to this treatment option {two patients [4.4%] in group [I] and 3 patients [6.7%] in group [II], also patients in Control group show non-significant subjective improvement. BTX-A could be a potential but not durable therapy for erectile dysfunction, as BTX-A [50 and 100 Unite] show almost same efficacy but, with complete follow up through 6 months, BTX-A 100U is more durable than 50U