SYNCHROS (SYNergies for Cohorts in Health: integrating the ROle of all Stakeholders) coordination and support action aims to establish a sustainable European strategy for the development of the next generation of integrated population, patient and clinical trial cohorts, thereby contributing to an international strategic agenda for enhanced coordination of cohorts globally. This will address the practical, ethical and legal, and the methodological challenge to optimising the exploitation of current and future cohort data, towards the development of stratified and personalised medicine as well as facilitating health policy. In order to achieve this objective, SYNCHROS will map the cohort landscape in Europe and large international initiatives, identify the best methods for integrating cohort data, identify solutions for addressing practical, ethical and legal challenges in integrating data across patient, clinical trial and population cohorts, and evaluate the use of emerging and new data collection technologies and types of data. Together with intensive stakeholder involvement (researchers, patients, funding bodies, clinicians, coordinators of previous harmonization and integration exercises), strategy briefs will be written and used to conduct stakeholder dialogues to generate consensus following a deliberative process and implementation science methods. We aim to make sustainable recommendations on standards to improve future sample, data collection and data sharing methods and disseminate this information so as to contribute to defining an international strategic agenda for better coordination of cohorts globally. SYNCHROS partners include a large range of expertise from epidemiology and clinical research to legal/ethical issues and anthropology, international organizations such as WHO and European infrastructures such as ECRIN.