B ASIC research into the etiology and pathogenesis of rheumatic fever is still urgently needed, since it is from sluch knowledge that ultimate control of the disease will be possible. However, one of our greatest practical problems in rheumatic fever prevention is not a lack of preventive measures, but rather a lack of effective application of available preventive meiasures. Many physicians, have the impression that rheumatic fever is no longer an important health problem in the United States. They do not see many cases in their practice,-the classical manifestations of rheumatic fever are, less common than a decade ago and the symptoms may be so mild that they may pas,s unnoticed. Therapeutic measures have also become more, effective so that fewer deaths result even from the more severe attacks. This is encouraging progress, but a look at some facts will reveal that much effort is, still needed to control this largely preventable disease (table 1). In 1954, 1,297 deaths were reported from acute rheumatic fever and rheumatic carditis. Another 18,256 deaths resulted from the effects of chronic rheumatic heart disease. This contrasts with poliomyelitis which resulted in 1,368 deaths during that year. Like poliomyelitis, rheumatic fever is largely a crippling disease, and it,s impact results mainly from chronic disability and, later, death from chronic rheumatic heart disease. Certainly, more than 19,000 deaths each year from the acute and chronic effects of rheumatic fever leave little room for complacency. Every State in the United States reported deaths from rheumatic fever and rheumatic heart disease in 1955. The age-adjusted death rates from rheumatic fever and rheumatic heart disease are as high in some southern States as in some northern States. However, in general, the death rates are higher in the Rocky Mountain areas, New England, and the Middle Atlantic States. In approximately 30 States, rheumatic fever is a reportable disease. But if we considered the number of reported cases as a true index of the actual number occurring, we would be greatly misled. For example, a comparison of the reported deaths from acute rheumatic fever and rheumatic carditis (table 1) with the total number of reported cases of rheumatic fever (see below) during the years 1949 through 1955 would imply a fatality rate ranging from approximately 50 to 30 percent. This obviously is not consistent with clinical experience.