Cutaneous plasmacytosis is a rare disorder characterized by multiple red-brown plaques, mainly on the trunk, which histologically show a marked hyperplasia of mature plasma cells with no mitotic figures or cellular atypia. It is sometimes accompanied by extracutaneous symptoms like lymphadenopathy or interstitial pneumonia, but without plasma cell infiltration. Although many treatments such as corticosteroid lesional injection, cyclophosphamide, melphalan, systemic PUVA, and local tacrolimus application have been introduced for cutaneous plasmacytosis, there is no reported post-treatment data on cutaneous plasmacytosis in Korea. We report a case of a Korean male patient who was diagnosed with cutaneous plasmacytosis which was improved by PUVA therapy.