Despite the vast array of available therapies for treating psoriasis, there remains a need for safer, more effective treatments. Topical tazarotene has been shown to be effective in treating mild-to-moderate psoriasis without causing the adverse effects, such as mucocutaneous toxicity, hyperostosis, and elevation in serum lipids, often associated with orally administered retinoids. A 2-week pretreatment with tazarotene 0.1% gel once daily, followed by tazarotene plus UVB therapy (tazarotene-UVB) 3 times per week for 10 weeks, was more effective than UVB therapy alone or in combination with vehicle gel in reducing plaque elevation, scaling, and erythema. The tazarotene-UVB treatment was well tolerated, and no phototoxicity was observed. Treatment success, defined as a moderate response or better in psoriatic lesions (ie, > or = 50% improvement in psoriatic lesions compared with baseline), was achieved within 32 days with the tazarotene-UVB treatment, compared with 67 days with UVB alone or UVB plus vehicle gel.