In the course of a standardized diagnostic programme LH, FSH, testosterone, prolactin and oestradiol were measured in 204 patients with erectile impotence (mean age 47.6 years). A purely organogenic abnormality was found in 125 (61.3%), a mixed organogenic-psychogenic one in 39 (19.1%), and a purely psychogenic one in 40 (19.6%). Thirteen patients (6.3%) had an abnormality of the hypothalamic-hypophyseal-gonadal axis, nine in addition had severe organogenic changes as the clear cause of the impotence. History and clinical findings were unremarkable in only one patient. Routine determination of hormones would seem to be cost-effective only if an important organic deficit has been excluded as the cause of an erection abnormality and therapeutic consequences can be drawn from any abnormal hormone values that are obtained.