In five per cent of impotent, sexual dysfunction obviously results from an organic factor which can be today qualified as "classical". "Hidden" organic factors have also been implicated in a variable ratio of the other cases. This paper constitutes a critical review of the role they play in impotence, and of the methods allowing their detection. On one hand, methods allowing evaluation of the respective responsibilities of organic and psychogenic factors (the most important of which remain nocturnal penile tumescence monitoring); on the other hand, specific investigations of each factor. It is no longer possible to deny the existence of "hidden" organic factors in impotence. These factors intervene to varying degrees in one third of cases. Among them erectile failure only by themselves. Hyperprolactinaemia, moderate hypogonadism, infraclinical neuropathies, arterial stenoses and moderate venous leakages seem to play a partial role of organic starter or cofactor, the sexual consequences of which are amplified by psychological factors, partly secondary to the initial sexual failures. Nevertheless, the conjunction of several "hidden" organic factors may probably be sufficient to induce an impotence without involvement of psychological factors.