The objective of the study was to compare the compliance and the side effects of a short course to treatment of latent tuberculosis infection during 3 months(isoniazid plus rifampin)group I, with the standard course for 6 months(isoniazid)group II .Prospective, comparative, randomized and open trial of patients with positive TST and the suitable criteria for treatment, in accordance with the guidelines of the CDC, excluding HIV infection. 105 patients were included. In Conclusion, a short course with isoniazid plus rifampin during 3 months shown better compliance with a lower percentage of abandonment that the course 6H. Tolerance is similar in the two courses.