Two cases of so‐called multicentric pigmented Bowen's disease were examined by electron microscopy. The three types of genital lesions found in Case 1, including typical black papules, whitish macerated papules and brownish‐black papillomatous lesions, showed both dyskeratotic features which were less pronounced than those of ordinary Bowen's disease, and virus‐like particles in the nuclei of the keratinocytes beneath the horny layer. On the other hand, the two types of lesions in Case 2 showed similar features, although dyskeratotic features were not apparently observed. These results suggest that the three types of genital lesions in Case 1 are similar to each other, and also to extragenital lesions, which were also present, and that there may be a common pathogenetic factor, probably human papilloma virus.