Background: Although PUVA treatment of psoriasis is more effective than conventional or broad-band UVB phototherapy, two small studies have suggested that narrow-band or TL-01 phototherapy may have a therapeutic effect equal to PUVA. If confirmed, this would be of considerable importance as TL-01 therapy is likely to be considerably safer in the long term than PUVA. Objective: The purpose of this study was to compare PUVA with narrow-band (TL-01) phototherapy in psoriasis. Methods: We studied 100 patients with plaque-type psoriasis who were randomly allocated to twice-weekly treatment with PUVA or narrow-band UVB. Results: Clearance of psoriasis was achieved in a significantly greater proportion of patients treated with PUVA (84%) than with TL-01 (63%) (P = .018), and with significantly fewer treatments (median number of treatments for clearance with PUVA, 16.7; with TL-01, 25.3; P = .001). Only 12% of those treated with TL-01 were clear of psoriasis 6 months after finishing treatment compared with 35% for PUVA (P = .002). Conclusion: When given twice weekly, PUVA is more effective for psoriasis than narrow-band UVB phototherapy. (J Am Acad Dermatol 1999;41:728-32.)