The increasing number of deinstitutionalized patients in crisis are placing new demands on general hospital emergency rooms. The authors discuss the approaches used in staffing and operating a psychiatric emergency service at a large general hospital in western Massachusetts. After studying the disposition of patients seen on the service, the authors determined that overnight hospitalization and crisis management could substantially reduce the need for longer hospital admissions. Subsequently a proposal was developed for a sevenbed emergency psychiatric treatment unit to provide brief, intensive psychiatric care for both voluntary and involuntary inpatients. The authors describe the staffing and layout of the unit, and the population to be served.