Despite the fact that life expectancy has nearly doubled over the past century, the US public has become increasingly preoccupied with issues of health and illness. In this study, the authors investigated cohort differences in self-rated health between women born in 1935-1944 (preboomers) and women born in 1945-1954 (baby boomers). A randomly selected, community-based sample of 618 mothers, 314 preboomers, and 304 baby boomers was interviewed. Over three decades, self-rated health was assessed in 1975, 1983, 1985-1986, 1991-1994, and 2001-2004. An individual growth model showed a linear decline (-0.61 per year, p<0.001) in self-rated health from mean ages 31-59 years combined, with a quadratic age effect (-0.03, p<0.001). Baby boomers reported lower self-rated health (mean difference, -5.30; p<0.001) and more rapid decline per year (slope difference, -0.52; p<0.001) than did preboomers of overlapping ages; those differences remained after adjusting for demographics, socioeconomic variables, personality factors, health behaviors, chronic illness, and depression symptoms. Study findings have important implications with regard to the potential growing burden on the nation's health care system, suggesting that generational changes in health evaluations and expectations may continue to increase demand for medical care.