The study is concerned with developing a typology of integration, scoping the need for, and current existence of, integration in Australia, and providing indicative findings on the effectiveness of integration involving homeless people with mental health conditions including substance use disorders. The present Positioning Paper reviews the literature on integration and provides preliminary descriptive results from case studies conducted with three medium-to-large community agencies providing specialist homelessness services (Ruah Community Services in Perth, The Haymarket Foundation in Sydney and HomeGround Services in Melbourne). The common feature of the three agencies chosen is that they manage a broad range of programs, including those with links to drug and alcohol services and mental health services.