Erectile dysfunction (ED) has been the most neglected complication of diabetes. It is a common abnormality that affects more than 20 million American men. The prevalence of ED in the general population between the ages of 40 to 70 years is 52%. In men with diabetes, it ranges from 35% to 75%, and occurs at an earlier age. There have been several advances in the understanding of the physiologic and biochemical mechanisms controlling penile erections. Improved techniques in diagnoses and treatment of impotence have given the male with diabetes some hope in the management of this prevalent and emotionally disturbing complication.