A 44-year-old man, who was seen for further examination of macroscopic hematuria, was found to have black eruptions on the penis and the scrotum. These eruptions appeared benign clinically, but on histological examination they showed the features of Bowen's disease. These eruptions were diagnosed as Bowenoid papulosis and were successfully treated with 5-FU cream. Twenty five cases of Bowenoid papulosis observed in men have been reported in Japan. Although Bowenoid papulosis is characterized by the histopathologic conditions of Bowen's disease, the lesions of Bowenoid papulosis differ clinically from those of Bowen's disease in several respects: onset at earlier average age, multiplicity of lesion, lack of associated symptoms, smaller size of the lesion, clinical morphologic features and possible spontaneous regression.