The primary objective of the Army psychiatric program is the reduction of non-effective military performance due to psychological causes. In recent years this program has been expanded to include disciplinary offenders as well as the usual psychiatric disease categories. To implement this program, psychiatric personnel have been displaced from the hospital or clinic setting to the military community. This field approach has made possible the utilization of milieu as a major instrument in the development of primary, secondary, and tertiary techniques of preventive psychiatry. Statistical data are submitted which indicate that the Army psychiatric program has made significant contributions towards achieving the lowest recorded psychiatric hospitalization and medical discharge rates, and a marked reduction of the Army prisoner population.