Performing high quality research into medicines and medical devices for children is indispensable to improve medical care for babies, children and young people – eventually improving the overall health outcomes of the next generation. Children should not be considered as small adults. Important differences to adulthood include the influences of different sleep and nutrition patterns, developing organ function, changes related to growth and body composition or influences of pubertal hormones. This necessitates adequate pre-trial planning defining relevant subgroups (i.e. neonates, pre-school, school-age, pubertal and post-pubertal adolescents) depending on the proposed indication of the drug in question. This includes age-appropriate information, consent and educational material. Presently, several medicines used in the pediatric age group are only approved for adults. They are used off-label where no appropriate paediatric medicine is available or has not been adequately tested in paediatric cohorts according to standards required by regulatory bodies. Indeed more than 50% of children's drugs are currently not tested or approved for children. Such off-label use includes legal and medical risks and lacks collection of evidence and pharmacovigilance. Thus, European networks of centers specialized for delivering state of art paediatric trials with appropriate paediatric as well as managerial experience and age-appropriate facilities are under development.