Etiology, pathogenesis and optimal therapy of Peyronie's disease are, 240 years after its first description, still unclear. Diagnosis includes palpation, measurement and exact drawing of the mostly dorsally and laterally located penile induration, photography of erectile deviation, cavernosography and ultrasound as follow-up controls. Pathogenesis of fibrotic stimulation is related to direct local causes such as vascular lesions, microtrauma and hemorrhage and to indirect induction of plasma exudation via autoimmune mechanisms by toxins, infections and vasoactive substances. Symptomatology in 116 of our own patients included the obligatory penile scar, erectile deviation in 75%, pain during erection in 33% and difficult or impossible intercourse in 40%. Radiotherapy in 113 patients led to healing or marked improvement in 44% of cases. In 41% the disease came to a standstill and in 15% of cases symptoms became worse. An analysis of the world literature shows surprisingly a 75% improvement by vitamin E therapy and almost a 60% amelioration by p-aminobenzoic acid and corticoid injections. Favorable results of radiotherapy vary in the literature between 50 and 70%. Reports on these successful treatments include unclear and optimistic criteria in small series and the possible spontaneous standstill or regression of the disease. Indications of operation are erectile pain, impossible invagination and a high degree of penile deviation. Surgical techniques are: (1) Excision of smaller fibrotic segments followed by longitudinal suture of the corpora cavernosa; (2) symmetric and cylindrical resection of both cavernous bodies followed by a watertight reanastomosis after mobilization of the corpus spongiosum; (3) after excision of larger plaques the defect may be covered by autologous material (danger: scar formation, aneurysmatic protrusion, impotence), and (4) hydraulic or semirigid penile prostheses are an ultima ratio. Since there was a 85% improvement or standstill of the disease and little side reactions in 113 of our patients following radiotherapy we recommend it particularly in the early inflammatory phase. An operation might be indicated for patients who do not benefit from this treatment and who show above-mentioned symptoms.