: Human papillomavirus (FIPV) infection plays a role in the development of Bowen's disease (BD). The aim of this study was to examine the correlation between HPV infection and Bowen's disease (BD), Bowen carcinoma (BC) and Bowenoid papulosis (BP). We investigated the occurrence of low-risk mucosal HPV (low-risk HPV) and high-risk mucosal HPV (highrisk HPV) in histological specimens obtained from 67 patients with BD in 52, BC in 13, and BP in 2 lesions by in situ hybridization (ISH). Low-risk HPV was detected in 4 lesions, whereas high-risk HPV was detected in 47 (70.1%) lesions. Using clinical data, high-risk HPV infection of BD and BC was observed in 27 of 32 lesions (84.4%) in males and in 18 of 33 lesions (54.5%) in females. Significant differences in the thickness of keratosis and the epidermis were evident between lesions positive for high-risk HPV and those negative for high-risk HPV infection. These findings show that there is a high level of high-risk HPV infection in BD, BC and BP lesions. The level of high-risk HPV was lower in BC than in BD, but not to a significant degree, therefore high-risk HPV may not participate in tumor cell invasion of dermis. Although a higher occurrence of high-risk HPV was observed in males than in females, the cause was unknowen. There was no correlation between the level of high-risk HPV and clinical features, including lesion location, size, disease duration and patient age. HPV increases keratinocytes, therefore the corneum and epidermis may be thicker in HPV-positive high-risk lesions than in HPV-negative lesions in BD and BC. It is highly likely that HPV infects more corrnified lesions.