Study objective: We describe, in comparison with a control group, frequent attenders to an emergency department in terms of their general health service use and their clinical, psychological, and social profiles.Methods: One hundred frequent attenders (those who had made A visits in the previous year) and 100 nonfrequent attenders matched for sex, age, and triage category were interviewed in the ED. Data were gathered on health service use, mental health (by using the General Health Questionnaire-12 item), and perceived social support (by using the Multidimensional Scale of Perceived Social Support). Patients' general practitioners were contacted to validate attendance data. Medical charts were searched for evidence of psychological problems and alcohol or drug abuse.Results: In the overall sample of 200 patients, 32% were female, and the mean age was 55 years (SO 20). Frequent attenders had made more visits to their general practitioner in the past year compared with control patients (median 12 versus 3 visits); a higher proportion of frequent attenders had used public health nursing services, community welfare services, social work services, addiction counseling, and psychiatric services in the past year. Frequent attenders had made more other hospital visits and had spent more nights in the hospital than control patients. General Health Questionnaire-12 item scores were higher for frequent attenders than control patients, indicating poorer mental health. Frequent attenders had lower levels of perceived social support.Conclusion: Frequent attenders to the ED are also heavy users of general practice services, other primary care services, and other hospital services. General Medical Services-eligible patients (84% of frequent attenders) frequently attend the ED, even though they have free access to primary care. Frequent attenders are a psychosocially vulnerable group, and service providers and policy makers need to take account of this vulnerable patient profile as they endeavor to meet their service needs.