Two hundred and eight acid-fast microorganisms were used in this investigation. ' Methods of isolating bacteriophages from soil, positive sputa, stool specimens, and from lysogenic strains are described. Eleven phages isolated from soil, their adaptation to other strains, and their characteristics are presented. Classification of these phages by plaque type and size, range of activity, cross-resistance tests, serological grouping, and morphology (some) are dealt with in detail. The phage preparations showed activity for 22 (44%) of 50 saprophytic strains tested. None were active against 120 human, 14 bovine, and eight avian tubercle bacilli. Though phage adsorption occurred onto some pathogenic strains it was not followed by phage multiplication and liberation. A tentative phage typing scheme is presented and discussed.