Case management arose in the USA as a solution to the difficulties of providing community care to people with severe mental disorders. The basic principle of the approach is that a case manager takes responsibility for a client; arranges an assessment of need, a comprehensive service plan, delivery of suitable services, and monitoring and assessment of services delivered. The case-management approach has been widely accepted, to the extent that recent legislation has made case-management the cornerstone of community care in the UK. We did a randomised controlled trial to evaluate a social services case-management team for people with long-term mental disorders. Subjects were referred from hostels for the homeless, night shelters, a general-practitioner clinic for the homeless, the Oxford City Council homelessness unit, and local voluntary-sector group homes. Of 103 subjects referred, 80 consented to be randomised to treatment or control groups. At 14-month follow-up, as assessed by standardised interviews, there were no significant differences between groups in number of needs, quality of life, employment status, quality of accommodation, social behaviour, or severity of psychiatric symptoms. In the case-management group there was a significant reduction in deviant behaviour on a standardised behaviour rating scale (REHAB) (mean = 0.79; 95% CI 0.26-1.32). It is unfortunate, in view of the limited effectiveness we have shown, that social services case-management was not evaluated in randomised controlled trials before its implementation in the UK.