Although the AIDS epidemic has had a major impact on the lives of women throughout the world, there is little knowledge regarding risk factors, transmission factors, prevention methods, and results of prevention efforts for older women, even though almost 10% of all AIDS cases in the United States are among those 50 years and older. This article reports results on AIDS knowledge and risks from the Massachusetts Women's Health Study, a longitudinal community-based study of middle-aged women. AIDS-related questions were asked of this sample at their last study interview, which occurred in 1995 when the women were aged 58-67. Results indicate that this sample of older, predominantly Caucasian women are quite knowledgeable about transmission factors but are less knowledgeable about early interventions and their own risk status. Many are also likely to know someone with HIV or AIDS. Even though these women are generally at low risk, they may be at higher risk than they perceive. They may also be significant disseminators of knowledge to friends and relatives who may be at risk, and thus could represent an important target group for AIDS educational programs.