Pigmented Bowen's disease (PBD) is a rare variant of Bowen's disease(BD). Most of the reported cases showed pigmented patches or thin plaques. Thus its clinical manifestations may simulated other various pigmented skin lesions. We experienced 2 cases of PBD in patients with multiple BD developed after taking Korean proprietary pills(KPP, "Hwan-Yak"), which were suspected to contain certain amount of arsenics. Both patients also showed arsenical keratosis on their palms and soles. The darker pigmentation of the PBL led us to differentiated them from melanoma.