Background:Whether physical activity (PA) and sedentary behavior influence the odds of women living to age 85 years without chronic disease or disability is not well described. Methods:Participants of the Women's Health Initiative (n = 49,612) were categorized based on health status by age 85 years: (i) lived without developing major chronic disease or mobility disability ("healthy"); (ii) lived and developed mobility disability with or without disease; (iii) lived and developed major chronic disease, but not mobility disability; and (iv) died before their 85th birth year. Multinomial logistic regression models that adjusted for covariates such as age, race/ethnicity, and body size estimated associations of self-reported PA and sitting time on developing major disease or mobility disability or dying before age 85 relative to being healthy. Results:Mean ± SD baseline age was 70.2 ± 3.6 years. Distributions were: 22% healthy, 23% had mobility disability, 26% had major disease, and 29% died. Relative to those with high total PA, the adjusted odds ratios (OR) (confidence intervals [CI]) for mobility disability was 1.6 (1.4-1.7), 1.2 (1.1-1.3), and 1.1 (1.0-1.2) for women with no, low, and moderate total PA, respectively (p-trend < .001). The corresponding covariate-adjusted OR (CI) for mortality was 1.7 (1.5-1.8), 1.2 (1.1-1.3), and 1.0 (1.0-1.1) (p-trend < .001). Total PA was not associated with developing chronic disease before age 85 years. Sitting ≥10 relative to <5 hours per day increased the odds of mobility disability (1.1, CI: 1.0-1.3) and mortality (1.2, CI: 1.0-1.3) prior to age 85 years (p < .001). Conclusions:Increasing PA to recommended levels and reducing sitting time are modifiable behaviors that may improve healthy aging in older women.