Topical tretinoin therapy produces clinical improvements in fine wrinkling of photodamaged skin by enhancement of collagen sytheesis. A major biochemically and histologically detectable change in the photodamaged skin is the accumulation of abnormal elastic fibers (elastotic material). However, little is known about the effects of retinoic acid and ultraviolet B(UVB) on elastin gene expression. Consequently we examined the effects of all-trans-retinoic acid (t-RA) and UVB on elastin gene expression in cultured human skin fibroblasts. Confluent dermal fibroblasts were irradiated with varying single doses of UVB (O, 3, 5, 10, 15, 20 mJ/cm 2 ). 24h following UVB irradiation, fibroblasts were harvested and some experiments were performed with pretreatment of t-RA. Northern blot analyses, chloramphenicol acetyl transferase(CAT) assay, and indirect immunofluolescence (IIF) studies demonstrated that t-RA down-regulates human elastin gene expression elevated by single exposure of UVB at transcriptional and post-transcriptional (protein) levels. These results suggest that anti-photoaging effect of t-RA is related, at least in part, to down-regulation of elastin gene expression elevated by UVB.