The activities covering a three-year period of a psychiatric home care treatment program attached to a psychiatric unit of a general hospital are described. A detailed account of its operation and the roles played by each member of the team is given. This service frequently provides a substitute for hospitalization in the management of both acute and chronic psychiatric states and thereby constitutes an important preventive measure in the field of public health. Even if the initial attitude of the patient is negative it is possible to gain the co-operation of the family who become a useful ally in the treatment. The co-operation of the patient is not as essential as has been thought. The traditional role of the psychiatrist is reversed by virtue of his attending the patient at home. The active participation of social agencies is an integral part of the treatment.