Several 5-alkyl (or halo)-3′-azido (amino or halo) analogs of pyrimidine nucleosides have been synthesized and evaluated against Mycobacterium bovis, Mycobacterium tuberculosis and Mycobacterium avium. Among these compounds, 3′-azido-5-ethyl-2′, 3′- dideoxyuridine (3) was found to have significant antimycobacterial activities against M. bovis (MIC50= 1μg/mL), M. tuberculosis (MIC50= 10μg/mL) and M. avium (MIC50= 10μg/mL).