Despite the increasing number of specialized addiction services and the constant deployment of health care resources, a coordinated needs-based treatment is not always available for people with severe drugs and/or alcohol problems. Too often the involved health care professionals feel helpless and overwhelmed by the complexity of the situation. In order to promote the treatment engagement of the hard-to-reach substance users, a multidisciplinary mobile team project for addiction (SIMA) was developed in Lausanne, Switzerland, in 20174. This paper describes the model of intervention, the profile of the population followed during the first year of intervention and illustrates, through two clinical cases, the advantages of this approach.