The retinoids are synthetic derivatives of vitamin A. Isotretinoin (13-cis-retinoic acid) is now being widely used in the United States for severe acne and etretinate is available in Europe and other countries for psoriasis. These drugs are also effective for a number of other skin diseases. This is an attempt to review basic knowledge of retinoids with which the practicing dermatologist should be familiar, to review the current status of studies, and to speculate on the present and future roles of these drugs in dermatology.