The following complexes of cefazolin(HCefaz) antibiotic were synthesized and investigated: [M(Cefaz)2].xH2O where M=Mn(II),Co(II) ,Cu(II);x=0,4,2and [M(Cefaz)y.Cl.H2O].xH2O where M = Fe(II), Co(II), Zn(II); y = 1; x=0,3,2 and M = Fe(III); y = 2; x = 3 .The complexes have been characterized on the basis of elemental analyses, IR, electronic and mass spectroscopy. The thermal behavior of the complexes was followed by thermo gravimetric analysis (TG) and differential thermogravimetry (DTG). The IR spectra showed that the ligand acts in a mononegative bidentate fashion. Preliminary pharmacological tests on cefazolin salt and its complexes exhibited some antimicrobial activity.