Although effective medications to treat and even prevent Tuberculosis (TB) have been available for over 40 years, TB remains the most important infectious cause of mortality among adults in the world. One of the cornerstones of control of this disease is detection and treatment of infection - while it is still latent, or dormant. Nine months of Isoniazid (INH) is highly effective to treat latent infection, and so is considered the standard therapy. However, this therapy is often unsuccessful, because the long duration reduces completion rates, and increases cost, and it is associated with serious, even fatal side effects. An alternate regiment, of four months Rifampin has been recommended by authoritative agencies as an alternative, but there is surprisingly little data regarding the safety and efficacy of this regimen. We propose a randomized trial to compare the rate of adverse event resulting in permanent discontinuation of study drug, with 4 months of Rifampin or 9 months of Isoniazid given as daily, self-administered treatment for LTBI.