Résumé : Reduction or dysfunction of the intracavernous smooth muscle fibers can provoke impotence. Computerized digital image analysis of corpus cavernosum biopsies was performed in potent and impotent patients to quantify the percentage of smooth muscle fibers. In 5 normal patients the smooth muscle area represented 40 to 52% of the specimen, in 20 patients with cavernous dysfunction it was 10 to 36% and in 10 patients with arterial disease it was 13 to 25%. This method appears to be important to understand better certain mechanisms of impotence and to approach the potential treatment.