AbstractThe first twin study in Serbia began in 2011 as a part of the research project, ‘Psychological Foundations of Mental Health: Hereditary and Environmental Factors’. At the same time, the research team from the Faculty of Philosophy and Faculty of Medicine in Novi Sad established the first Serbian twin registry. The registry is intended primarily for the purpose of the research in behavioral genetics, as well as potential future studies in human genetics. It includes information on 1658 volunteers, including twin-pairs, their parent and siblings. The behavioral genetic study of adult twins has been focused on the hereditary and environmental sources of variance of different psychological characteristics, such as personality traits, cognitive abilities, executive functions and aggression, as well as some anthropometric measures and aspects of mental and physical health. Certain molecular genetic analyses have also been performed. The research team is currently starting the longitudinal twin study of children, which will be focused on different indicators of emotional, cognitive and physical development.