Abstract Purpose Sexual activity is an important component of quality of life for women across their lifespan. Prior studies show a decline in sexual activity with age, but these studies often fail to consider the role of sexual satisfaction. The aim of this study is to give updated prevalence estimates of sexual activity among women and to elucidate factors associated with sexual activity and sexual satisfaction. Methods We report a cross-sectional analysis of the second wave of a nationally representative sample of US adults aged 28 to 84 years, the Survey of Midlife Development in the United States. The survey used self-administered questionnaires to assess demographic data, self-rated physical and mental health, medical problems and medication use, relationship factors, and sexual activity and satisfaction. Results Of 2,116 women who answered the questions regarding sexuality, 1,345 (61.8%) women were sexually active in the previous 6 months. The proportion of women who were sexually active decreased with advancing age. Women who were married or cohabitating had approximately 8 times higher odds of being sexually active (odds ratio = 7.91, 95% CI, 4.16-15.04; P <.001). Among women aged 60 years and older who were married or cohabitating, most (59.0%) were sexually active. Among women who were sexually active, higher relationship satisfaction ( P <.001), better communication ( P = .011), and higher importance of sex P = .040) were related to higher sexual satisfaction, but age was not ( P = .79). Conclusions A considerable proportion of midlife and older women remain sexually active if they have a partner available. Psychosocial factors (relationship satisfaction, communication with romantic partner, and importance of sex) matter more to sexual satisfaction than aging among midlife and older women.