Erectile dysfunction and impotence has a high prevalence among male hypertensive patients. Whether this relates mainly to specific drug side effects or to primary pathogenic disorders is unknown. In the present study 101 male patients from our outpatient hypertension clinic answered detailed questionnaires about hypertension and sexual function. Patients with perceived impotence were offered a thorough penile evaluation and examination performed by specialists in the urology department. Twenty-seven (27%) men had impotence. The main cause of impotence was an arterial dysfunction (89%). The prevalence of impotence was related to the degree of secondary organ manifestation, reflected by World Health Organization (WHO) classification I-III (P = .01). Intermittent claudication (P = .001) and ischemic heart disease (P = .005) were the best determinants in this respect. Twelve impotent patients (44%) ascribed onset of impotence to drug initiation. A variety of drugs were incriminated in the occurrence of drug-induced impotence. In summary our results indicate that impotence in hypertensive men is caused mainly by penile arterial vascular changes, probably atherosclerosis. Drug-induced impotence could well be the result of blood pressure reduction itself and not specific drug side effects.