Sexual impotent is very common entity and define as inability to induce or maintaining penile erection during sexual intercourse. Studies reveals about 10% of men aged 40-70 years have complete, 17% have mild and 25% have moderate amount of erectile dysfunction.The sexual impotence has different etiology including psychogenic, neurogenic, arteriogenic and venogenic causes.Current studies reveal that organic cause of impotent is a bout 50-90% cases.Among them vascular reasons including arterial insufficiency or venous incompetence contributed 50-70% cases (arteriogenic impotence 30%, venogenic impotence 15% and 25% mixed Venus and arterial).Diagnosis of an organic cause of impotence is very important because is could be curable.The cavernosal arteries are the main feeders to penis and where the erection is performed. Selective angiography with selective internal pudendal is an invasive but the gold standard in evaluation of penile arteries in evaluating arteriogenic impotence.This technique is invasive and is not suitable as a first step or screening examination.Color doppler imaging could be a suitable technique inassessement of vasculogenic impotence during injection of an intra cavernosal vasodilating pharmacological agent and observing the response.By color doppler imaging blood velocity mof cavernosal arteries could be measured before and after intracavernosal injection of vasodilating agents.Also increase in size of the vessel diameter (0.75%) is an indication of normal arterial flow. A suitable vasodilator could be intrcavernosal injection of 60 mg of Papavarine in a 2 ml solution into right or left corpus cavernosum.Alternative drugs are cocktail of triple agent consisting of Papavarine 4.4 mg, phentolamine 0.15 mg and PG-E1.Drug induced priapism may occur in 2-3% of the patients.The patient can be divided into normal, with an average PSV of 47 cm/second, B. Mild to moderate with average peak systolic velocity (PSV) of 35 cm/second and C. Severe arterial insufficiency with an average PSV of 7 cm/second.Generally peak systolic velocity of 40 cm/second was normal.The parameters that indicate the presence of arterial disease are a subnormal clinical response to vasoactive agents, a less than 60% increase in the diameter of the cavernosal artery, and a peak systolic velocity of the cavernosal arteries less than 25 cm/second.In the presence of normal arterial function, doppler findings suggestive of an abnormal venous leak are persistent end diastolic velocity of the cavernosal artery greater than 5 cm/second and demonstration of flow in the deep dorsal vein.The development of diastolic flow reversal after an injection has been found to be a reliable indicator of venous competence.In conclusion color duplex doppler ultrasoung with intracavernosla injection of vasodilator. Sonography is an excellent and accurate means of assessing patients with erectile dysfunction. It is a minimal invasive test with low complication rate and can produce good results and should replace angiography and cavernosometry as primary or screening test.