A UV source of low-intensity output with peak effective emission in the 300 to 320-nm range, termed low-intensity selective UV phototherapy (LISUP), is being advocated for home phototherapy for psoriasis. Twenty patients with plaque-type psoriasis were treated three times a week as outpatients with this unit; the results were compared with those found in a similar group of 20 outpatients treated previously three times a week with a proved and effective protocol using erythemogenic exposures to a conventional UV-B source. Emollients were the only topical agents used during therapy. Eight patients had clearing and five others showed improvement with LISUP. Eighteen patients had clearing and one showed improvement with the UV-B protocol. We found LISUP less frequently effective when used three times a week in clearing plaque-type psoriasis. Therefore, we recommend a trial of this unit before purchase by the patient.