Retinoids are potent therapuetic agents that have been found to be effective in a variety of skin diseases. They are of benefit in various forms of severe psoriasis. With severe plaque psoriasis, they are used most effectively in combination with other forms of therapy, such as phototherapy. With generalized pustular psoriasis, they are effective monotherapy and are frequently helpful for the control of exfoliative psoriasis. A variety of new retinoid analogs have been studied in clinical investigations. This article discusses important aspects of the use of etretinate, isotretinoin, acitretin, and arotinoid ethyl ester in the treatment of severe forms of psoriasis.