City4Age (Elderly-friendly city services for active and healthy ageing) is a research and innovation project funded by the European Commission under the Horizon 2020 Programme. The first and core objective of City4Age is to enable Ambient Assisted Cities or Age-friendly Cities. The project aims to create an innovative framework on ICT tools and services that can be deployed by European cities in order to: enhance early detection of risk related to frailty and Mild Cognitive Impairments (MCI), and provide personalised intervention that can help the elderly population to improve their daily life and also promote positive behaviour changes. The dataset contains the data captured during the 6 pilots (Madrid, Birmingham, Montpellier, Lecce, Singapore and Athens), being composed by the users’ activities and behavior both inside their home and in the city. The dataset is divided into two parts: 1) the ‘low elementary actions’ which contains the basic actions; 2) the measures which are physiological values of the monitored users. The file ‘data_format.zip’ contains the description of the dataset.