Some new N-[3-(2-oxo-1, 2-dihydro-indol-3-ylidene-hydrazinocarbonyl) benzyl] benzamide (III) have been synthesised from different isatin derivatives (I) by condensing with N-[3- (Hydrazinocarbonyl) benzyl] benzamide (II). Their chemical structures have been confirmed by IR, 1H NMR, Mass and by elemental analysis. Investigation of antimicrobial activity of compounds was done by the disk diffusion technique. Among the compounds tested, the compound with 5-Cl, 5-I substitution showed the most favourable antimicrobial activity.