The benefits of hormone replacement therapy (HRT) in HIV-negative postmenopausal women include the abatement of menopausal symptoms such as hot flashes, insomnia, mood changes, vaginal dryness, urogenital and skin changes, and memory loss. HRT may also decrease risk for primary cardiovascular disease, osteoporosis, colon cancer, and possibly Alzheimer's disease and age-related macular degeneration. There may also be an overall survival benefit for HIV-negative postmenopausal women taking hormone replacement therapy. Despite the potential benefits of postmenopausal hormone replacement, it is seldom used in HIV-infected postmenopausal women. One concern about HRT in HIV-infected women is the potential for interaction with antiretroviral (ARV) drugs. Although the effect of HRT on ARV drug levels is likely to be small, it is important to evaluate the safety of administering HRT concurrently with ARVs. The information obtained from this study will help shape recommendations for postmenopausal HRT in HIV-infected women.