A novel Schiff base, benzylmethyl-4-methyl-3-thiosemicarbazone (BMM) derived from benzylmethylketone and 4-methylthiosemicarbazide was synthesized and characterized by elemental analysis, spectroscopic methods (IR, 1 H NMR, 13 C NMR) and physical means. The single crystal structure analysis of the Schiff base reveals that it crystallizes in a monoclinic system in the P2 1 /c space group. BMM revealed moderate antibacterial activity on three bacterial strains with diameter zone of inhibition of 16 mm (E. coli), 14 mm (K. pneumonia) and 13 mm (S. epidermidis) compared with the standard drug, ciprofloxacin.