Assertive Community Treatment (ACT) or Assertive outreach is not a treatment but a way of organising and delivering care via a specialised team to provide intensive, highly co-ordinated and flexible support and treatment for clients with longer term needs living in the community. To be effective, teams must deliver a mix of evidence based psychosocial intervention and intensive practical support from multi-skilled and multi-disciplinary practitioners. This lecture will focus on an overview of ACT development in Spain and a number of issues affecting the implementation of ACT services. The Assertive Community Treatment team of Avilés (Asturias, Spain) was the first ACT service-delivery model implemented in Spain. It started in 1999 as an effort to give an answer to the increasing needs of patients with the most severe and persistent mental illnesses and their families. Due to lack of previous community-based programs following ACT model in Spain, our development process and start-up procedure have guided a number of similar teams all over our country.