OBJECTIVE: Involuntary outpatient commitment has been used as a method of improving tenure in community programs for individuals with severe and persistent mental illness. This paper reviews literature on research about involuntary outpatient commitment and suggests questions and methods for future research. METHODS: Literature describing research studies of involuntary outpatient commitment, located by searching MEDLINE and following up references cited in relevant articles, was reviewed with attention to patient characteristics and diagnostic, treatment, and outcomes measures. RESULTS: Involuntary outpatient commitment appears to provide limited but improved outcomes in rates of rehospitalization and lengths of hospital stay. Variability in community treatment makes interpretation of other types of outcome difficult. Few studies specifically identify results among patients with severe and persistent mental illness. CONCLUSIONS: No studies have examined the extent to which outpatient commitment affects compliance and treatment when essential community services such as case management are consistently and aggressively provided, nor have studies controlled for potentially confounding factors such as treatment and nontreatment effects, including informal coercion. A randomized trial of involuntary outpatient commitment should be useful in evaluating the effectiveness of this type of intervention.