The metal complexes of cefoperazone with transition metals (Cr(III), Mn(II), Fe(III), Co(II), Ni(II), Cu(II), Zn(II), Cd(II) and Hg(II)) were synthesized. From IR spectra proved that cefoperazone acts as bidentate ligand. The active sites for coordination of cefoperazone were confirmed by using the hyper-chemistry program. The magnetic measurement and spectral data proved octahedral structure for all complexes except that of Ni, Cu and Hg, those have tetrahedral structural. The thermal decomposition mechanisms of the prepared complexes were studied and suggested. The kinetic and thermodynamic parameters of the thermal decomposition steps, Ea, ∆H*and ∆S*, were estimated from DTA thermograms. Cefoperazone complexes showed higher activity than commercial cefoperazone for some strains.