Retinoids are a fascinating class of compounds that exert control over cellular function from the time of conception to death. They play a critical role in such vital processes as fetal morphogenesis, cellular differentiation and apoptosis. Over the years synthetic retinoids have provided dermatologists with a spectrum of medications that have profound therapeutic effects on a variety of recalcitrant skin disorders. Moreover, retinoids are an expanding component of the treatment arsenal against hematologic and solid malignancies. Retinoids are poised to offer exciting new therapeutic options in the field of endocrinology for the treatment of diabetes and lipid disorders. Researchers and clinicians are only beginning to unveil the therapeutic potential of this class of medications. The development of new retinoid compounds targeting specific receptors promises a wealth of new therapies for the new millennium.