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 (MIC(50)=1μg/mL), M. tuberculosis (MIC(50)=10μg/mL) and M. avium (MIC(50)=10μg/mL).