Antibodies to three mycobacterial antigens, Soviet tuberculin and ultrasound-treated Mycobacterium tuberculosis (H37Rv) and M. bovis (BCG) were detected by enzyme immunoassay in 90 patients with pulmonary tuberculosis and 75 normal subjects. Antibody detection rates and levels were found related to the form of tuberculous process. The detection rate was rather low in focal tuberculosis and virtually the same for all the antigens (15.3 percent). In disseminated processes (infiltrative and particularly disseminated and fibrous-cavernous) antibodies are detected more often in higher titers than in local processes, and their levels are different with different antigens. The method was more sensitive with ultrasound-treated antigens of M. tuberculosis (H37RV) and M. bovis (BCG) than with PPD. Simultaneous enzyme immunoassay with three antigens detected up to 75 percent of antituberculous antibodies in infiltrative, up to 92 percent of antibodies in disseminated, and up to 100 percent of antibodies in fibrous-cavernous tuberculosis.