Topically applied 2% minoxidil solution has been reported to increase diameter, rigidity and arterial flow to the penis. As a result it has been suggested as a possible treatment for erectile dysfunction. A total of 21 patients received 2% minoxidil for treatment of erectile dysfunction with instructions to apply 1 cc of the solution slowly over the glans penis 20 minutes before intercourse. Average patient age was 52.5 years (range 29 to 65 years). The etiology of the impotence was neurogenic in 8 patients, vascular in 7, psychogenic in 4 and other causes in 2. Two patients also had clinical evidence of venous incompetence and 4 were diabetics. One patient with psychogenic impotence noticed improvement in the duration of erection but no increase in rigidity or size after minoxidil application. One patient with impotence after excision of a Peyronie’s plaque reported a rigid erection adequate for intercourse after using minoxidil. This patient subsequently was able to achieve erections without using minoxidil. The remaining 19 patients had no improvement in erectile rigidity or the ability to obtain or maintain an erection. One patient did notice some mild burning on the glans penis after applying the minoxidil. No other side effects were noted in any patient. These results indicate that 2% topical minoxidil solution is not effective when applied to the penis in the treatment of erectile dysfunction. It is possible that a higher concentration, a different delivery medium or a different chemical composition may yield better results.