This chapter presents the factors relevant to assessing sleep problems in the menopausal transition that have changed over time. Expectations regarding menopause have changed over time, particularly since the advent of hormone replacement therapy. Increasing interest in reproductive aging and the advent of women's health as a specialty has led to a great deal of research on the menopausal transition. It is possible that there has been an increase in sleep disturbances in women across all menopausal status categories, but that the rank order of increasing prevalence of sleep problems among pre-, peri-, and post-menopausal women prevails. Preliminary analyses from the "Sleep in Midlife Woman" sub study, with biannual in-home polysomnography, continue to support the hypothesis that the risk of sleep apnea increases with advancement through the menopausal transition. There are important clinical implications from current thinking on sleep in the menopausal transition.