The results of a study by the Tuberculosis Chemotherapy Centre, Madras, of the merits of home as compared with sanatorium treatment for pulmonary tuberculosis have indicated that treatment at home is satisfactory in the majority of cases. Before domiciliary chemotherapy can be introduced on a large scale, however, it must be established that it does not expose the patient's contacts to a special risk of infection, avoided by his isolation in a sanatorium. Accordingly, a further study was undertaken by the Centre to determine (a) the prevalence of tuberculosis among the family contacts of patients, and (b) the incidence of clinical tuberculosis and of tuberculous infections in the family contacts of the home and sanatorium groups of patients during the first year of treatment. The findings of this study indicate that the major risk for contacts lies in exposure to the infectious case before diagnosis, whether the patient subsequently remains at home or is isolated in a sanatorium appearing to have little importance, if the patients at home are treated with effective chemotherapy. Children under seven years of age proved to be particularly vulnerable to infection. The management of young contacts by chemoprophylaxis or by BCG vaccination, or by both measures, has been discussed.