Aseries of isonicotinoylhydrazones 2 were prepared by addition of some aryloxyacetonitriles with isonicotinoylhydrazine in basic medium. These compounds have been further reacted with pyridinecarboxaldehydes to give the corresponding pyridylmethyleneamino derivatives 3–5. The new synthesized hydrazones and their pyridylmethyleneamino derivatives were tested for their activity against mycobacteria, Gram-positive and Gram-negative bacteria. The cytotoxicity was also tested. Several compounds showed a good activity against Mycobacterium tuberculosis H37Rv and some isonycotinoylhydrazones 2 showed a moderate activity against a clinically isolated M. tuberculosis which was isoniazid resistant.