To assess the activity of clofazimine (CFZ) against Mycobacterium tuberculosis persisters using an oxygen depletion model and a low-dose aerosol mouse model of chronic tuberculosis (TB). In in vitro experiments, CFZ showed much better activity than isoniazid under anaerobic conditions. In a low-dose aerosol mouse model of TB, we evaluated the efficacy of CFZ and moxifloxacin at different doses following treatment durations of 30, 60 and 90 days. CFZ showed significant bactericidal activity in the mouse model over the wide dose range of 2-200 mg/kg. CFZ activity was dose-dependent. The bacilli were eradicated in the CFZ 200 mg/kg group after treatment for 60 days, and in the CFZ 20 mg/kg group after 90 days of treatment. CFZ exhibits dose-dependent, sustained bactericidal activity against M. tuberculosis persisters, and thus warrants further study to demonstrate its potential to contribute significantly in a novel treatment-shortening regimen.