Project Connect, a clinical demonstration program developed in consultation with the New York State Office of Mental Health, adapted critical time intervention for frequent users of a large urban psychiatric emergency room (ER). Peer staff provided frequent users with time-limited care coordination. Participants increased their use of outpatient services over 12 months, compared with a similar group not enrolled in the program. For persons with significant general medical, psychiatric, and social needs, provision of this intervention alone is unlikely to reduce reliance on ERs, especially among homeless individuals.