Assertive Community Treatment (ACT) is a well-defined service delivery model for the care and treatment of the most severely mentally ill in the community. We have opted for a Dutch version named 'Function' ACT or FACT. In a FACT team, ACT is one of the functions that the team can perform. For more stable long-term patients FACT provides coordinated multidisciplinary treatment and care by individual case management. Unstable patients at risk of relapse are followed with assertive outreach care by the same team, working with a shared caseload for this subgroup. This article describes the service model and everyday practice in FACT.