This article emphasizes the seriousness of the problem of chronic disease. It is estimated that some 25 million persons suffer from some disabling or non-disabling chronic ailment in the United States alone. Measured by disability, chronic diseases and impairments are responsible for the loss from work of almost a billion days each year. Nervous and mental diseases, rheumatism, heart disease, hypertension and arteriosclerosis, tuberculosis and cancer account for half of this loss. It is pointed out that chronic disease is not a problem only of old age. More than half of all persons with known chronic diseases are less than 45 yrs. old. Chronic diseases require a large share of medical and hospital services. Three of 4 hospital patients in this country are hospitalized for chronic physical or mental disease. The need for the integration of psychiatry in the public health program is stressed. Adequate organized control of cardiac disease among adults, rheumatism, and other major chronic diseases require increasing attention to the psychic as well as the somatic aspects of the problem. Postwar planning should include exploration of the most effective uses and application of psychiatry in the prevention and treatment of chronic disease.