Seventy patients with various forms of psoriasis were treated topically and orally with 8-MOP and UVA in high or low intensity treatment units. Most of the patients were treated with the oral route. Treatment modalities, age distribution, and medical history of psoriasis are compiled. The present investigations are based upon experiences with three treatment units, a horizontal box, a stand-up box, and a hand-foot-box. The mean exposure time and the mean duration of treatment are compared. Advantage and disadvantage of oral vz. topical 8-MOP-UVA-therapy are discussed. The typical treatment-schedule with determination of minimal phototoxic dose, initial treatment and maintenance irradiation are described. Side-effects are reported. A careful selection of patients for PUVA-therapy is stressed. Possible long-term side-effects are considered.