Objective: To compare the efficacy of narrowband UV-B (TL-01) phototherapy with oral 8-methoxy-psoralen photochemotherapy (8-MOP psoralen-UV-A [PUVA]) in patients with chronic plaque psoriasis (CPP). Design: Open, randomized, controlled study Setting: Phototherapy unit in a dermatology hospital. Patients: Fifty-four patients with CCP, Interventions: Patients received whole-body threshold erythemogenic dose of either 3-times weekly TL-01 or twice-weekly oral S-MOP PUVA, based on minimal erythema or phototoxic doses. Patients were treated until completely clear. Outcome Measures: Number of treatments to clear, number of days in treatment, number of days in remission, and adverse effects of both therapies were assessed. Results: Forty-five patients completed the study. Those in the PUVA group required significantly fewer treatments to clear (P = .03). There was no significant difference in the number of days to clear or number of days in remission. A similar percentage of patients in the TL-01 and PUVA groups developed minimal perceptible erythema, showing that the regimens were equally erythemogenic. Asymptomatic, well-defined erythema occurred only in the PUVA group, Pruritus and polymorphic light eruption occurred equally in both groups, but only patients in the PUVA group developed nausea. Conclusion: Narrowband UV-B phototherapy, used 3 times weekly, is as effective for the treatment of CPP as oral 8-MOP PUVA used twice weekly.