Authors outline the differences between medical and psychiatric definition of emergency and analyze different organizational models of psychiatric intervention in Emergency Room. The historical evolution changed these models, and the relation with services for acute and subacute patients in hospital and community services. The Italian reform model is compared with the slow deinstitutionalization of psychiatry in other countries. Critical points in Italian emergency organization after the Psychiatric Reform are pointed out: low number of beds for acute patients, difficulties and delays in transfer from Emergency Room to GHPW (General Hospital Psychiatric Ward), waiting lists for voluntary treatments. To overcome some of these problems, the Authors propose that even in hospitals without psychiatric ward, a small unit of short psychiatric observation be implemented, for voluntary treatments, before transfer to other institutions.