The ATHLOS (Ageing Trajectories of Health: Longitudinal Opportunities and Synergies) Project officially began May 1st 2015. The ATHLOS Kick-off Meeting was held May 11th and 12th, 2015 in Barcelona, organised by the coordinator (Parc Sanitari Sant Joan de Déu -PSSJD) and with the participation of all the partners involved in ATHLOS. After welcoming the participants to the meeting, Dr Josep Maria Haro provided a general outline of ATHLOS, and each partner made a presentation of their group and institution. The different work packages were presented by their Principal Investigators, and participants were given an overview of all longitudinal data sets to be considered in ATHLOS. The event was also attended by the officer of the European Commission in charge of supervising the project.