For most patients with erectile dysfunction oral agents are a preferred treatment option. Oral or buccal phentolamine has been shown to produce full erections in impotent subsets of study populations. We evaluate the efficacy of oral phentolamine. After a comprehensive evaluation 44 patients with recent onset (less than 3 years) of erectile dysfunction and a high likelihood of organogenic etiology underwent a prospective, double-blind and placebo controlled trial with oral phentolamine after placebo. After placebo 4 of the 44 patients who reported full erections were excluded from study. Of the 40 patients in the double-blind phase full erections were achieved by 2 of 10 with placebo, and 3 of 10 with 20 mg., 5 of 10 with 40 mg. and 4 of 10 with 60 mg. phentolamine. There were no serious complications observed during the study, and only a single minor side effect occurred in 1 patient after 60 mg. phentolamine. Our results indicate that oral phentolamine may be of benefit for the treatment of erectile dysfunction. Further studies are required to corroborate our findings.