Purpose: The Future Occupation of Children and Adolescents cohort (the FOCA cohort) is a large population-based cohort study that was established as a resource for research in order to study adolescence factors and future educational and vocational trajectories in a life-course perspective. The cohort covers a broad array of themes within public health, including diseases and health behaviours. Through linkage to register data on the participants' parents, the cohort allows investigation of parental effects over time on adolescents' behaviours and interactions across generations. Participants: The FOCA cohort consists of 13 100 adolescents attending ninth grade in Denmark during the first quarter of 2017, independent of school type. Findings to date: Included were 6685 girls (51.03%) and 6415 boys (48.97%) with an average age of 15.85 years, representing 650 schools (37.23%), covering all options in the Danish school system and widely distributed across the country. The use of the personal identification number allowed for a merge of parents to all adolescents in the cohort, resulting in the identification of 25 911 registered parents. Register data on parents' socio-economic position and labour market history showed representativeness among the adolescents' socio-economic background compared with the general population in Denmark. Future plans: The adolescents will be followed by ongoing linkage to administrative registers. Future studies will focus on factors affecting future health, education, work and well-being in a life-course perspective and for specific research projects, it will be possible to apply for permission to link data to further ongoing national registers covering all participants.