SummaryBackground Previous investigations have demonstrated that a combination of etanercept (ETN) and narrowband ultraviolet B (NB-UVB) phototherapy is more effective than ETN alone. However, it is unclear if this combination is more effective than NB-UVB phototherapy alone. Objectives To evaluate whether the combination of NB-UVB phototherapy with ETN improves the efficacy of ETN alone in the treatment of moderate-to-severe psoriasis. Methods We enrolled 322 consecutive patients with moderate-to-severe plaquetype psoriasis, who were treated with NB-UVB phototherapy as the first-line treatment option. Patients who did not achieve a 75% improvement in Psoriasis Area and Severity Index (PASI 75) were treated with conventional systemic therapies for psoriasis. If they were ineligible for these, they were treated with ETN 50 mg twice weekly. If they did not achieve PASI 75 within 12 weeks, NB-UVB phototherapy was added. Results PASI 75 was achieved in 262 patients (81Á4%) treated with NB-UVB phototherapy. Sixteen patients (5Á0%) dropped out for personal reasons and 24 (7Á5%) were treated with at least one of the conventional systemic treatments for psoriasis. Twenty patients (6Á2%) were treated with ETN. The combination regimen was needed in eight patients (2Á5%) with poor response to both phototherapy and ETN alone. All of these patients achieved PASI 75 and three of them had a complete remission after 14Á6 AE 3Á3 NB-UVB exposures. The combined treatment was well tolerated without acute adverse events. Unfortunately, all of these patients relapsed, with PASI > 10 within 2Á8 AE 1Á7 months. Conclusions The combined treatment has a synergistic effect for clearing plaquetype psoriasis previously unresponsive to ETN and NB-UVB phototherapy alone. The clearance rate is very high in a very short time without short-term adverse effects. However, concerns regarding potential cocarcinogenicity remain. Therefore the number of patients who require, and could benefit from, the combined treatment is likely to be small.