The records of 40 patients with miliary tuberculosis and 24 others with both tuberculosis and significant hematologic abnormalities were reviewed to see if the hematologic changes represented primary diseases or were secondary to tuberculosis. Leukopenia, leukocytosis, monocytosis, and anemia are certainly responses to tuberculosis because they disappear following antituberculous treatment. Patients with tuberculosis and leukemic blood pictures or pancytopenia do not survive with use of antituberculous therapy alone. A likely explanation for this is that underlying hematologic disease is present and greatly contributes to the invariably fatal outcome. Since no patient with tuberculosis and pancytopenia has been reported to recover with antituberculous therapy alone, there appears to be no basis for considering tuberculosis a "treatable cause" of pancytopenia.