The results of treatment, including all chemotherapy regimens, in 353 cases of miliary tuberculosis in adults revealed a mortality of 16%. Mortality after the introduction of isoniazid was only 5%, and no relapse of miliary disease occurred. Mortality among 217 patients with both miliary and meningeal involvement prior to the use of isoniazid was 90%, but decreased nearly 4-fold, to 23%, with the use of this drug. Meningeal involvement following the onset of miliary tuberculosis did not occur after the addition of isoniazid to the therapy. There were few tuberculous complications following the start of chemotherapy. More than 70% of the survivors of both miliary and miliary-meningeal disease are able to work. Despite the very high incidence of miliary tuberculosis among Negroes, the mortality rate was markedly lower than in white patients. The morbidity and mortality from miliary or miliary-meningeal disease should improve with early recognition and initiation of effective therapy, employing combinations of antimicrobial agents containing isoniazid and maintained for 24 months or more.