We describe each childhood background measure available in the National Social Life, Health, and Aging Project (NSHAP), report preliminary population estimates for each measure by age and gender, and validate the childhood measures by showing that the associations between the NSHAP childhood measures and later-life health outcomes are consistent with previous studies on this topic. Childhood background measures included family life happiness, family structure, parental educational attainment, perceived financial situation, experience of violence, witness of violence, childhood health, and place of birth. We measured self-rated health, depressive symptoms, and social support to assess later-life physical, mental, and social health. Logistic and linear regression models were used for the binary and continuous outcome variables, respectively. Older age groups were more likely than those in younger age groups to report a poor financial situation in childhood, lower parental education, and intact family structure and were less likely to have experienced or witnessed a violent event as a child. Growing up in a happy and well-educated family was associated with better physical, mental, and social health in older ages. NSHAP childhood data included a variety of measures assessing the family social environment during childhood, providing a valuable resource for the study of early-life determinants of health and well-being over the life course.