There has been growing concern about the increasing numbers of homeless people with mental ill health, many of whom may be falling through the "net" of mental health services [1]. A recent large UK study [2]-which excludes Northern Ireland (NI)-provided a comprehensive picture of the prevalence of mental morbidity among homeless people. However, there is still some uncertainty about the extent and severity of mental disorders among this population. Furthermore, hostel staff in Belfast (NI) and elsewhere have expressed concerns about their capacity to provide appropriate care and support. Approximately 1 percent of the NI population (21,000) were registered as "statutory homeless" (i.e., as opposed to the "hidden homeless") during 1995-96,40 percent of whom were considered "vulnerable" (e.g., because of physical or mental disability).