Objectives: Quality of life (QOL) data were used to evaluate the effects of self-administered intracavernosal injection of alprostadil for erectile dysfunction, when used for up to 18 months during a 13 country Phase III clinical trial. Methods: The Duke Health Pro®le was used to measure patients' physical and psychosocial QOL at baseline, 3, 6, 12 and 18 months. Changes from baseline were measured using paired t-tests, with additional analyses by cause of dysfunction, starting dosage, and prior treatment. Results: Patients displayed signi®cant improvements in mental and social health and self-esteem at six months (P`0.01, n 570), with greater improvements at 12 and 18 months. Anxiety and depression measures also improved signi®cantly at 12 and 18 months, as did the summary general health score. Worse pain scores were observed in the ®rst year but not at 18 months. Those with a starting dosage of 10±20 mg, those with psychogenic causes of dysfunction, and those with no prior treatment for erectile dysfunction generally showed the greatest improvements. Conclusion: In this study, the clinical improvements in erectile function due to intracavernosal alprostadil therapy were complemented by QOL improvements, particularly in the mental health, of many patients.