Papilloma which develops in the head and neck is known to exhibit different clinical features depending on the region, age of onset and tumor growth. We detected human papillomavirus (HPV) DNA using molecular biological methods, and evaluated the characteristics of HPV infection. The subjects examined were 8 cases of laryngeal papilloma, 17 of nasal papilloma, 21 of oral papilloma, 1 of pharyngeal papilloma and 1 of esophageal papilloma. The detection rate of HPV was 100% in the larynx, 29% in the nasal cavity, and 5% in the oral cavity, showing a large difference in the detection rate depending on the region. As a whole, the detection rate of HPV was higher in the upper airway, while almost no HPV was detected in the upper digestive tract. In the current examination, either HPV6a or HPV11a was detected in all cases of laryngeal papilloma, suggesting that HPV plays a very important role in the development of laryngeal papilloma. However, there was no specific relationship between the type of HPV and the age of onset or tumor growth. Among the nasal papilloma cases, one case each of HPV6a, HPV11a and unknown-type HPV was detected in exophytic nasal papilloma. In the inverted papilloma cases, although HPV was detected in two of 14 cases, we could not classify the HPV into any of the known types. There was a large difference in the detection rate of HPV between different modes of tumor growth: the detection rate of HPV in the exophytic type was 100%, while that in the inverted type was 14%. In 21 cases of oral papilloma, with the exception of the case in which HPV6a was detected at the floor of the mouth, no HPV was detected in any case including the 15 cases with papilloma of the soft palate. These results suggest that HPV influences tumor development differently in oral papilloma even when macroscopic and histological findings are the same as those of laryngeal or nasal papilloma, and that there are differences in the mechanism of development and exacerbating factors of these tumors. In the two cases of laryngeal papilloma in which HPV6a was detected, a deletion was found in the non-coding region. However, there was no difference in clinical features between these two cases. The difference in the HPV detection rate is related to clinical features, showing that HPV greatly influences the clinical features of tumors.