Cefotaxime (Hcefotax) interacts with transition metal ions to give [M(cefotax)Cl] complexes (M = Mn(II), Fe(III), Co(II), Ni(II), Cu(II) and Cd(II)) which were characterized by physicochemical and spectroscopic methods and a tetrahedral geometry is suggested for their structure. The IR and the ¹H-NMR spectra of the complexes suggest that the cefotaxime behaves as monoanionic tridentate ligand . The complexes have been screened for antibacterial activity against several bacteria, and the results are compared with the activity of cefotaxime