Abstract Body: Introduction: Lifestyle factors such as achieving recommended levels of aerobic moderate to vigorous physical activity (MVPA) intensity (>150 min/wk), sedentary behavior (SB) (<8h/d), and sleep duration (7-9h/d) comprise the 24-hour movement paradigm and are independently linked to mortality risk. Limited evidence exists on whether adherence to the 24-Hour Movement Guidelines (24H-MG) in combination is associated with mortality risk. Purpose: Examine the association of meeting the 24H-MG and risk of cardiovascular disease mortality (CVD) and all-cause mortality and estimate the number of deaths that could be prevented by meeting all components of the 24H-MG in a national representative sample of US adults. Methods: Participants enrolled in the 2005 and 2010 National Health Interview Survey were analyzed. MVPA, SB, and sleep were self-reported. Mortality was ascertained from National Death Index through December 31, 2019. Meeting a 24H-MG was classified by meeting following criteria sleep 7-9h/d, SB <8h/d, and MVPA >150 min/wk. Results: Among US adults, 4.9% (95% CI 4.6- 5.2), 23.9% (23.4-24.5), 44.6% (44.0-45.2), 26.6% (26.0-27.2) met 0,1, 2, or all 3 24H-MG respectively. After adjusting for covariates and excluding deaths in the first two years, meeting a greater number of 24H-MG was associated with lower risk of all-cause mortality in a dose-dependent fashion over a median follow-up of 9.9 years (Figure, Panel A). Hazard ratios (HR [95% CI]) comparing US adults meeting 1, 2 or 3 guidelines versus meeting 0 guidelines were 0.71 (0.59-0.85), 0.61 (0.51-0.73), and 0.52 (0.43-0.64), respectively (p-trend <0.001). Meeting a greater number of 24H-MG was also associated with a reduced risk of CVD (Figure, Panel B): HRs=0.85 (0.60, 1.21), 0.75 (0.53, 1.06), 0.42 (0.28, 0.63) for meeting 1, 2 or 3 guidelines, respectively, versus meeting 0 guidelines (p-trend <0.001). By targeting all but those who meet all 3 movement guidelines, 16.8% (95% CI: 13.7-19.0) of total deaths and 38.7% (95% CI: 31.0-41.4) of CVD deaths could be prevented by shifting US adults to meet all 3 guidelines. Conclusions: In a national representative sample of US adults, there is a dose-response association between meeting 24-hour movement guidelines and mortality risk. Meeting all three guidelines was associated with a 48% reduced risk of all-cause mortality and 58% reduced risk of CVD. These findings support the need to promote a healthy 24-hours to reduce mortality risk in US adults.