Complete eradication of tuberculosis as a major cause of illness and death in the United States within the next generation or two is an attainable possibility by application of methods already known. If streptomycin or a similar drug proves efficacious this time would be considerably shortened. In the over-all fight against the disease the physician whose practice deals with children can contribute much in this final drive. Diagnostic tuberculin is one of the most specific of all the specific tests available for the detection of disease. The physician should use it routinely in his child patients at two to three year intervals. False negative tests occur only rarely. A positive test means only that a primary tuberculous infection has occurred at some previous time. However, the finding of a positive reaction in a child, especially a young child in the first years of life, may be the means of uncovering an hitherto unsuspected source of contagion. Furthermore, a positive test in a child identifies the individual who must be kept under observation for the possible development of chronic pulmonary tuberculosis at some future date. Mass x-raying the chests of children fails to make this distinction. Knowledge of the pathogenetic development of the various forms of tuberculosis aids the physician in recognizing the stage in the evolutionary course of the disease at which his patient may have arrived. There are fundamental differences between primary tuberculosis and reinfection tuberculosis. The development of tuberculoallergy several weeks after the initial infection is responsible for these differences. In the majority of children primary tuberculosis is limited to the pneumonic lesion and to the lymph node lesion. In a few, extension may occur by contiguity about the pulmonary focus, or by hematogenous or bronchogenic spread from the lymphnode focus. Thus accounted for are the acute reinfection forms of tuberculosis such as tuberculous broncho-pneumonia, miliary tuberculosis, and tuberculous meningitis. The latter, however, is not the direct result of hematogenous seeding, but rather, results from rupture of an older focus into the sub-arachnoid space. Chronic pulmonary tuberculosis is rarely encountered before puberty. No certain explanation exists for the remarkable freedom children between the ages of five and puberty enjoy from tuberculous morbidity and mortality. Possible factors having a bearing upon the high infection rate of chronic reinfection tuberculosis, especially in girls, during the teen age are the increased need for minerals and protein and other metabolic changes which occur in adolescence in association with the establishment of menses. The reaction of every child to tuberculin should be known at or before the onset of puberty. Positive reactors should have, at least annual x-ray films of the lungs made in order to recognize at the earliest possible time, the characteristic soft mottled apical shadows of the early infilliate. Diagnostic tuberculin and the x-ray constitute the bulwarks upon which chief dependence is placed for the diagnosis of the various forms of tuberculous disease occuring in childhood. History of exposure, symptoms of illness and physical findings are relatively poor guide posts. Demonstration of tubercle bacilli by gastric lavage is frequently helpful in clinching a previously suspected diagnosis. Studies of the blood, including the hemogram, sedimentation rate and Schilling differential count are of less value in diagnosis than in estimating prognosis and the favorable or unfavorable course of the disease. The immediate prognosis of all primary tuberculous infections is good, with the exception of the comparatively few children in the first five years of life whose primary complexes extend to the development of such acute reinfection forms as meningitis, miliary disease and tuberculous pneumonia. The remote prognosis however, is more uncertain, both from the point of view of the number who will ultimately develop chronic pulmonary tuberculosis and the number who will die from this form of the disease. An environment safe from the risks of tuberculosis infection should be provided every child. In this preventive phase the pediatrician and the physician can accomplish much. Experiments now being carried on with streptomycin may provide a specific form of therapy, but until its efficacy has been proven, rest, diet, healthful living conditions and time are the general measures to be relied upon for bringing about healing in most of the tuberculous lesions of children. Collapse therapy may occasionally be indicated.