This study describes the treatment of Peyronie's disease by means of low-dose radiotherapy. We treated 265 men aged 24.5-79.4 years (median = 57.7 years). No previous therapy had been carried out in 214 patients, and 41 patients had been pretreated (systemic: potassium p-aminobenzoate, vitamins a, b, e; topical: corticosteroids, teleradiotherapy). The disease was classified using criteria proposed by Alth in 1984 location, number and size of foci, hardness of fibromatous foci and axis deviation, potentia coeundi and pain were evaluated). Radiotherapy was performed by local application of a special iridium-192 moulage developed at our institute. In 66.4% of the monitored patient group (n = 155) therapy was successful. We obtained complete regression of the fibromatous foci in 9% (n = 14), partial remission > 50% in 29.7% (n = 46) and partial remission < 50% in 27.7% (n = 43) of the patients. We found a significant correlation between hardness, size of the treated foci and therapeutic success. Eighty-three patients suffered from pain during penile erection before therapy, and in 61.4% (n = 51) of these patients the pain disappeared after treatment. Moreover, the patients confirmed that both loss of pain and regression of deviation related to foci regressions were correlated with improvement in erectile function. No serious side effects were observed in any of our patients.