Objectives To determine the prevalence of Peyronie's disease, a localized connective tissue disorder of the penile tunica albuginea, the symptoms of which include palpable plaque, painful erections and curvature of the penis, in a large sample of men in Germany. Subjects and methods A standardized questionnaire was sent to 8000 male inhabitants (age range 30±80 years) of the greater Cologne area (< 1.5 million inhabitants). Three questions about the selfdiagnosis of Peyronie's disease were previously assessed for validity on 158 healthy men and 24 patients with con®rmed Peyronie's disease. To optimize the response rate, the questionnaire was mailed three times to all the men. Results The response rate after the third mailing was 55.4% (4432 men); 142 men (3.2%, mean age 57.4 years, SD 13.4) reported the new appearance of a palpable plaque which, from the previous validation, was the most sensitive question and the main symptom of the disease. In men aged 30±39 years only 1.5% reported localized penile induration, compared with 3.0% in those 40±49 and 50±59 years, 4.0% in those 60±69 years and 6.5% of those >70 years old. Newly occurring angulation was reported by 119 of the 142 men (84%) and painful erection by 66 (46.5%). The combination of the three symptoms (plaque, deviation and painful erection) was reported by 46 of the 4432 respondents (1.04%), i.e. 32% of the 142 men with penile induration; 58 of the 142 men (41%) reported erectile dysfunction. Conclusions This is the ®rst large cross-sectional, community-based study to examine the prevalence of Peyronie's disease. Using previously validated questions the prevalence of Peyronie's disease in the sample was 3.2%; this is much higher than indicated in previous reports. A comparably high prevalence is reported for diabetes and urolithiasis, suggesting that this`rare' disease is more widespread than previously thought.