We recently experienced one each of 2 types of recurrent respiratory papillomatosis (RRP). Case 1 (juvenile-onset type): A 30-year-old woman presenting with bloody sputum and large tumors with cavities on her chest X-ray film, was referred to our hospital. She had been diagnosed with laryngeal papillomatosis when she was three years old. According to our bronchoscopical examination biopsy, she was diagnosed with squamous cell carcinoma of the lung in addition to papillomatosis of the trachea and bronchus. Although chemotherapy was performed, she died 2 years after the diagnosis of lung cancer without any distinct treatment efficacy. Case 2 (adult-onset type): A 43 year-old woman presenting with fever and dry cough visited our hospital. Chest CT revealed that there was narrowing of bilateral main bronchi and hilar lymphadenopathy. Bronchoscopic examination revealed diffuse papilloma distributed extensively from the trachea to bilateral main bronchi. However, she recovered spontaneously in 6 months and has remained stable without recurrence. Both cases were diagnosed with RRP based on the separation of HPV in case 1 and pathological findings of koilocytosis in case 2. Case 1 was complicated with squamous cell carcinoma of the lung in the clinical course, presumably due to occurrence of malignant conversion of papillomatosis. Since RRP is a rare but refractory disease, novel effective treatment is necessary.