This chapter describes the work of a community mental health service for street homeless people in South London (the START Homeless Outreach Team) and is written by two clinical psychologists with current and previous experience of working in this service. The issue of homelessness is particularly relevant to this book because existing evidence reveals there to be a much higher proportion of street homeless men compared to women. To explore the issue of male homelessness and mental health in more depth, this chapter presents an overview and discussion of relevant literature. The chapter also considers the clinical implications of the issues discussed, which are illustrated by presenting an overview of the work of START and by describing an in-depth clinical case example.