Research on multimorbidity has rapidly increased in the last decade, but evidence on the effectiveness of interventions to improve outcomes in patients with multimorbidity is limited. The European Commission is co-funding a large collaborative project named Joint Action on Chronic Diseases and Promoting Healthy Ageing across the Life Cycle (JA-CHRODIS) in the context of the 2nd EU Health Programme 2008–2013. The present manuscript summarizes first results of the JA-CHRODIS, focuses on the identification of a population with multimorbidity who has a high or very high care demand.