The Integrated Services Project for Clients with Challenging Behaviour (ISP) aims to decrease the adverse impact of challenging behaviour on clients, the community, and the service system. The Project does this by developing intervention and support plans that better respond to the individual needs of clients with challenging behaviour, as well as improving their service access, housing, health and social conditions. The ISP is delivered through the NSW Department of Ageing, Disability and Home Care in cooperation with the NSW Department of Health and Housing NSW. The present document provides a preliminary cost effectiveness analysis based on initial client outcomes. The report begins with a brief overview of the ISP before describing the approach taken to the cost effectiveness analysis and the broad characteristics of the 38 ISP clients who were in ISP 2-32 months, from October 2005 to March 2008. The report analyses client outcomes in the following key areas: changes in challenging behaviour; client perceptions of personal wellbeing and health; living skills; social and economic participation; and changes in the use of community health, hospital, and criminal justice services.