BACKGROUND Despite the recent improvements in performing radical retropubic prostatectomy that have led to a considerable decrease in the complication rate, erectile dysfunction still represents a major problem. Moreover, less invasive treatment options that are emerging for erectile dysfunction have not shown satisfactory results in managing these patients. OBJECTIVE To study the efficacy and side effects of self-injection therapy in the treatment of men who had become impotent after undergoing radical prostatectomy due to prostate cancer, over a study period of 96 months. METHODS Observational study. METHODS University Referral Center. METHODS 168 patients with erectile dysfunction, aged 43 to 78 years old, who underwent radical retropubic prostatectomy due to localized prostate cancer. METHODS The patients were treated with self-injection therapy using papaverine, phentolamine and prostaglandin E1, at home. RESULTS This study showed an acceptable 94.6% success rate, with no life-threatening complications. In addition to this, our series presented a 13.1% cure rate with this therapy. CONCLUSIONS Self-injection therapy with papaverine, phentolamine and prostaglandin E1 is effective and safe in the treatment of erectile dysfunction after radical prostatectomy.