In vitro anti-mycobacterial activities of several 5-substituted acyclic pyrimidine nucleosides containing 1-(2-hydroxyethoxy)methyl and 1-[(2-hydroxy-1-(hydroxymethyl) ethoxy)methyl] acyclic moieties are investigated against three mycobacteria viz. Mycobacterium tuberculosis, Mycobacterium bovis, and Mycobacterium avium, which cause serious infections and mortality in healthy people as well as patients with AIDS. 1-(2-Hydroxyethoxy)methyl-5-(1-azido-2-haloethyl or 1-azidovinyl) analogs (4-7), 1-[(2-hydroxy-1-(hydroxymethyl)ethoxy)methyl]-5-decynyluracil (37), and 1-[(2-hydroxy-1-(hydroxymethyl)ethoxy)methyl]-5-dodecynyluracil (38) exhibited significant in vitro anti-tubercular activity against these mycobacteria.