New developments in the topical therapy and phototherapy of psoriasis have greatly improved our ability to safely and effectively treat this debilitating disease. Topical corticosteroids remain the most commonly prescribed agents for psoriasis, but they are frequently prescribed with other agents. Investigations of corticosteroids claiming an improved benefit/risk ratio have yielded promising results, but more work is needed. Use of anthralin and tar has declined with the availability of the noncorticosteroids calcipotriene and tazarotene. Other experimental topical therapies are in various stages of development. Broadband ultraviolet B (UVB) remains the most commonly used phototherapy light source, but many patients are being treated with a new form of ultraviolet light, narrowband UVB. Although PUVA remains one of the most effective psoriasis treatments, its use is declining because of its association with cutaneous malignancies. New radiation sources such as lasers have been added to our armamentarium of available therapies and even newer light source-based treatments are being examined. (J Am Acad Dermatol 2001;45:487-98.) Learning objective: At the conclusion of this learning activity, participants should be familiar with the varying topical treatments for psoriasis as well as the different modalities of phototherapy. Participants should also have a better understanding of side effects associated with each treatment, which should help in determining options for therapy.