Echo Doppler flowmetric investigation in patients with erectile insufficiency represents an effective method for hemodynamic evaluation of the penis. The detection of referential standard parameters is helpful to understand the pathogenesis of the disease, since patients with erectile insufficiency due to psychogenic factors cannot be distinguished from normal subjects by means of current diagnostic techniques. Echo Doppler flowmetry applied to rigorously selected subjects with psychogenic impotence allowed for detection of hemodynamic parameters in the penis after corpora cavernosa stimulation with 10 mug. prostaglandin E1. Flowmetric investigation was performed only on the deep cavernous artery, since it is well known that the penile dorsal artery does not undergo hemodynamic alterations after stimulation with drugs. A statistically meaningful difference existed between the systolic flow in the psychogenic impotence subjects (group 1) and the controls (group 2, p <0.0001). In the same manner, the diastolic flows (right and left cavernous arteries, p <0.0002 and p <0.0001, respectively) and diameter increase rates of the investigated arteries following stimulation were also different. According to these results, echo Doppler flowmetry could represent the only instrumental method able to detect patients with psychogenic impotence.