Number of acid hydrazide derivatives, as given in the accompanying Table, were prepared and their antibacterial activity, in vitro, was examined in Lockemann-Bloch medium, using the so-called “Mycobacterium tuberculosis A. T. C. C. No. 607, ” with isonicotinic acid hydrazide (INAH) as the control. The compounds which possessed activities equal to or almost equal to INAH were those in which carbonyl compounds such as acetone (No. 7 in Table) or glucose (No. 8) were bonded to the amino group in INAH, or the one (No. 9) in which sodium hdyroxymethane sulfonate was bonded. The compounds marked with asterisks in the Table are new compounds prepared for the first time.