Estrogens exert a protective effect against atherosclerosis. It is well known that hormone replacement therapy (HRT) can effectively decrease LDL-cholesterol and increase HDL-cholesterol and Apo-Al serum levels. Some recent studies have suggested that estrogens alone or in association with progestins may exert an antioxidant effect on lipids. Besides sex steroids, also vitamins exert an antioxidant effect on LDL and may preserve the endogenous antioxidants of LDL. The aim of our study was to evaluate whether HRT can improve alpha-tocopherol and beta-carotene serum levels in post-menopausal women. Fifteen postmenopausal women with climacteric symptoms were treated with 50 micrograms/24 h estradiol transdermally applied twice a week for 21 days. A daily dose of 10 mg oral medroxyprogesterone acetate was added for 12 days in each treatment cycle. This therapy lasted 6 months. A significant reduction was found in total cholesterol and LDL-cholesterol after treatment. Besides, our study has shown that alpha-toc/LDL and beta-car/LDL ratios significatively increased after treatment, while alpha-tocopherol and beta-carotene serum levels did not change significantly after therapy. These preliminary findings suggest that HRT can preserve the content of alpha-tocopherol and beta-carotene in LDL particles and keep the LDL in a reduced antioxidant state.