In this study Benzenesulfonicacid-1-methylhydrazide (bsmh) derivatives such as salicylaldehyde benzenesulfonylhydrazone (Hsalbsmh) and its Ni(II), Pd(II), Pt(II), Cu(II), Co(II) complexes were synthesized for the first time. The structure of these complexes was investigated by using elemental analyses, the FT-IR, LC-MS and UV-VIS spectrophotometric methods, magnetic susceptibility and conductivity measurement techniques. The complexes were found to have general compositions [ML(2)] Using disk diffusion methods all the synthesized complexes were evaluated in vitro as antimicrobial agents against representative strains of gram-positive (Staphylococcus aureus ATCC 25923, Bacillus cereus ATCC 11778, Enterococcus faecalis ATCC 29212, Bacillus subtilis ATCC 6633, Staphylococcus epidermidis ATCC 12228, Enterobacter aerogenes ATCC 13048) and gram-negative bacteria (Pseudomonas fluorescens ATCC 49838, Klebsiella pneumoniae ATCC 13883, Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853) and as an antifungal agent against Candida albicans (ATCC 90028). All the bacteria and fungus studied were screened against some antibiotics to compare with our chemical zone diameters. Published by Elsevier B.V.