Adult-onset laryngeal papillomatosis is a frequently relapsing disease affecting especially males. We studied the history and prevalence of extralaryngeal HPV infections in these patients to find out their susceptibility to HPV. Of adult-onset laryngeal papilloma male patients treated at Helsinki University Central Hospital over 25 years, we examined 50 for clinical findings, examined Pap and cytological samples from the oral mucosa and urethra and biopsied HPV-suspect lesions. Fifteen female sexual partners underwent gynecological examinations. The history of HPV-associated diseases was also determined from age- and sex-matched control subjects. Of the patients, 16% (8) had a history of genital warts and of the controls, 12.5% (6 of 48). A history of skin warts was more common in patients. Their prevalence of genital warts was higher (3 of 50, 6%) than in the general population (1%, earlier study). Prevalence of oral HPV DNA was 8% (4 of 50). Patients' sexual habits were unexceptional except for an over-representation of high-frequency orogenital sex initiated at a mean of 9.7 years before diagnosis. However, a lack of orogenital contact did not protect them from severe laryngeal disease. Patients with adult-onset laryngeal papillomatosis seem to be prone to HPV infections. Primary laryngeal HPV infection in adolescence may remain latent, requiring cofactors to develop into the clinical disease.