The two phages obtained from mycobacterium lepraemurium strain "Douglas" by using M. segmatis ATCC 607 as a non-lysogenic indicator (kindly supplied by L. Sula and named as AL1 and 1/1) were adsorbed on M. Smegmatis ATCC 607 with a P 45'/P0 of 0.046 and 0.01, respectively. Ultrastructural studies showed that these phages could be classified as Bradley type B1.