Caveolin-1 is regulated by estrogen in vascular smooth muscle cells. Raloxifene, a selectiveestrogen receptor modulator that possibly has cardioprotective properties without an increased risk of c ancer or other side effects of estrogen, may be used in women with risk of coronary artery disease. However, the relationship between raloxifene and caveolin-1 is still unknown. Therefore, this study was designed to see whether raloxifene regulates caveolin- 1 expression and if so, whether such regulation is mediated by estrogen receptor. Rat aortic smooth muscle cells were cultured in the absence or presence of raloxifene (10-8 to 10-6 M) for 12 or 24 h. Both mRNA and protein levels of caveolin-1 were increased significantly after 24 h treatment with raloxifene. These increases were inhibited by estrogen receptor antagonist ICI 182780 (10-5 M). Results of this study suggest that raloxifene stimulates caveolin- 1 transcription and translation through estrogen receptor mediated mechanisms.