One hundred and seventeen children with pulmonary tuberculosis underwent treatment with a 6-month daily regimen of rifampin (15 mg/kg/day) and isoniazid (10 mg/kg/day). The criteria for the diagnosis of pulmonary tuberculosis were (1) clinical symptoms and signs in 93 children (79%), (2) history of direct contact with an adult with tuberculosis in 106 children (91%), (3) tuberculin reaction of 5 mm or more, without previous bacillus Calmette-Guérin (BCG), in 45 children (38%), (4) suggestive radiologic alterations in all patients, and (5) positive bacteriology or histology in four patients (3%). The treatment was completed by 97 children (83%). The mean weight gain during therapy was 2,145 g. There was an excellent clinicoradiologic response to the treatment, and improvement in chest roentgenograms was observed in all patients at the end of therapy. No relapses occurred among the patients followed for an average of 21.4 months. This study indicates that the treatment of primary pulmonary tuberculosis in children with a combination of rifampin and isoniazid daily for 6 months is efficacious and does not result in any relapse.