Mobility is critical to ageing well. However, only a minority of elderly people reach the recommended level of physical activity. In this context, the MobilityMotivator project has as an objective to promote mobility of elderly people by developing a serious gaming environment. This project follows a four-step plan: (1) a specification phase, (2) a prototype development phase, (3) an evaluation phase; and (4) a dissemination phase. At the end of the project, the MobilityMotivator platform will include two modes: an activity mode dedicated to elderly people in which they will perform different challenges and a measure mode in which physicians will be able to assess the progress and performance of their patients. The conclusion of this project will enable us to determine the impact of such an approach on the quality of life of elderly people, including the socio-economic impact.