Methanesulfonicacid hydrazide (a sulfonamide compound, msh: CH3SO2NHNH2) derivatives: salicylalde hydemethanesulfonylhydrazone (salmsh), 2-hydroxyacetophenonemethanesulfonyl hydrazone (afmsh), 2-hydroxy-3-metoxybenzaldehydemethanesulfonylhydrazone (o-vanmsh) and their Ni(II), Pd(II) and Pt (II) complexes have been synthesized. The structure of these compounds has been investigated by using elemental analyses; FT-IR, H-1 NMR, LC-MS, UV-Visible spectrometric methods; magnetic susceptibility; conductivity measurements; thermal studies. The antibacterial activities of synthesized compounds have been determined in vitro against gram positive bacteria; Staphylococcus aureus ATCC 25923, Bacillus cereus RSKK 709, and gram negative bacteria; Pseudomonos aeruginosa ATCC 27853, Escherichia coli ATCC 35268 by paper disc diffusion and microdilution broth methods. The biological activity screening showed that metal complexes have more activity than their ligands against the tested bacteria. (C) 2013 Elsevier B.V. All rights reserved.