This study investigates the relationship between DNA methylation-derived measures of accelerated aging (Δage) and all-cause mortality in four longitudinal cohorts of older individuals. Δage is calculated as the difference between DNA methylation-predicted age and chronological age. The results show that a 5-year higher Δage is associated with a 21% higher mortality risk, adjusting for age and sex. After further adjustments for childhood IQ, education, social class, hypertension, diabetes, cardiovascular disease, and APOE ε4 status, the increased mortality risk is reduced to 16%. Heritability analysis of Δage in a separate cohort indicates that approximately 40% of the interindividual differences in Δage are due to genetic factors. The findings suggest that DNA methylation-derived measures of accelerated aging are heritable traits that predict mortality independently of health status, lifestyle factors, and known genetic factors.This study investigates the relationship between DNA methylation-derived measures of accelerated aging (Δage) and all-cause mortality in four longitudinal cohorts of older individuals. Δage is calculated as the difference between DNA methylation-predicted age and chronological age. The results show that a 5-year higher Δage is associated with a 21% higher mortality risk, adjusting for age and sex. After further adjustments for childhood IQ, education, social class, hypertension, diabetes, cardiovascular disease, and APOE ε4 status, the increased mortality risk is reduced to 16%. Heritability analysis of Δage in a separate cohort indicates that approximately 40% of the interindividual differences in Δage are due to genetic factors. The findings suggest that DNA methylation-derived measures of accelerated aging are heritable traits that predict mortality independently of health status, lifestyle factors, and known genetic factors.