My research is carried out as part of the Children’s Worlds project. This international comparative project aims to collect questionnaire based data on children’s lives and daily activities as well as on their own perceptions and evaluations of their well-being. The talk is divided into three parts. Part 1 deals with the conceptual background of the study, the development of the notions like quality of life, social indicators, well-being and subjective well-being. Part 2 is devoted to methodological challenges like using survey tools for investigating young children aged between 8 and 12 years old. Sampling problems and validity and reliability of the data are discussed. Data allows insights into children’s view on their home environment and family relations, friendship connections, their life in school and inform about children’s and parental well-being as well as the connection between well-being and school performance. Part 3 reflects on the selected issues of the findings in Hungary