The National Longitudinal Study of Adolescent to Adult Health (Add Health) is a nationally representative longitudinal cohort study that sampled 20, 745 respondents in grades 7–12 (aged 12–19 years) at study inception in 1994–1995 and has followed them through six waves of data collection to date. At each wave, Add Health has collected measures of demographic, social, economic, psychological, and biological factors that provide a rich resource for the study of adolescent and young adult factors as they relate to the development of cardiovascular health and disease over the life course. Add Health has also appended thousands of contextual and environmental variables to geocoded, respondent residences over time. The three most recent follow-ups of the cohort (Waves IV–VI) include biomarkers of cardiovascular health such as body mass index, blood pressures, and concentrations of glucose, lipids, and cholesterol. All told, Add Health provides rich multi-level and longitudinal data among a diverse cohort of Americans for the scientific community to understand the development of cardiovascular health, disease, and disparities therein.