Juvenile laryngeal papillomatosis is characterized by benign budding tumors, developing from the endolaryngeal epithelium. Because the evolution of these tumors is unpredictable, choice of the best therapy is difficult. We report two cases where invasive juvenile laryngeal papillomatosis, progressively colonized the trachea and bronchi. Malignant transformation occurred without carcinoma predisposing factors. In both cases patients died after pulmonary dissemination. We discuss the role of the human papilloma virus and the high interest of viral typing, for an early diagnosis of possible degeneration. The choice of the best therapy, chemotherapy, CO2 laser, alpha interferon or auto-vaccination will depend on the type on the papilloma virus.