In a group of 179 patients treated for recurrent laryngeal papillomatosis 668 surgeries were performed in the years 1982-1995 in the Department of Otorhinolaryngology, Head and Neck Surgery in Prague. The group was divided into 77 patients with a juvenile form of papillomatosis and 102 patients with an adult form. The adult form was then divided into a multiple (65 patients) and solitary form (37 patients). Three patients with a juvenile form of papillomatosis were irradiated in advance. None of these patients developed a carcinoma. There were 3 cases (1.7%) of carcinoma in the whole group of patients with histologically verified papillomas during repeated previous surgeries. All 3 patients with malignancy had an adult form of papillomatosis, two with a multiple form and one with a solitary form. The intervals between the first treatment for papilloma and the diagnosis of carcinoma was 8, 3 and 2 years.The rates of malignant transformation of papillomas vary in the literature. We suppose, that because of the generally long interval between the diagnosis of papilloma and that of carcinoma, to make a final conclusion of a certain ratio is very difficult. We envisage that in our group of patients with papillomatosis new cases of carcinoma will occur in the future.