Several biological active metal complexes of cefazolin were prepared with stochiometries 1:1 and 1:2 (M:L) and characterized using (IR/, UV-Vis, ESR, magnetic susceptibility, thermal (TGA and DTA). Statistical studies gave different correlation coefficients between data. Mode of bonding of the investigated compounds: IR spectra assigned the different modes of vibrations of the fundamental functional groups in the compounds under consideration. On complexation, the shifts of the characteristic IR frequencies serve as a convenient measure of the character of the complex formed. In all complexes, the oxygen atom of (lactam carbonyl, carboxylic or amide carbonyl groups) and the nitrogen atom of amino thiazole ring are involved in chelation. Electronic absorption spectra gathered with the magnetic moment values pointed to that all chromium, manganese, iron, cobalt and complexes are of octahedral geometry and with high spin magnetic moment except nickel and mercury with tetrahedral geometry. The calculated room temperature powdered ESR data of copper cefazolin complex with the formula, [Cu(cefazolin)2Cl(H2O)] is of anisotropic nature.