Psoriasis is an inflammatory disorder of the skin that involves complex interactions between the dermis and epidermis. There are several forms of psoriasis, the most common being plaque type psoriasis. Other forms include guttate, pustular and erythrodermic psoriasis. Both the skin and joints are affected in this disease. Psoriasis ranges in severity from a few small plaques to involvement of the entire cutaneous surface. Therapy of psoriasis depends on the location, type and severity of the disease. Treatments include a wide array of topical medications including tars, anthralin, topical corticosteroids, vitamin D(3) analogs, retinoids and over-the-counter preparations. Phototherapy with ultraviolet B and PUVA are used for more widespread involvement. Common systemic therapies include methotrexate, retinoids and cyclosporin. This article will review the pathogenesis and clinical features of psoriasis, as well as current and future therapies.