Negative experiences in childhood can not only affect a child’s development, but also impair health and well-being in adulthood. The aim of the Level 3 project is to analyse the role of negative childhood experiences in health and social development in later life using an online questionnaire completed by participants in the German National Cohort (NAKO) in Halle. Data on negative childhood experiences are collected using the German version of the ACE questionnaire, which examines a wide range of early childhood traumatic stressors.