To overcome the alarming problem of microbial resistance to antibiotics, the discovery of metal complex drugs are found to be more effective than parent drugs to inhibit the microbial resistance to antibiotics.In this work, Co(II) mixed ligand complexes ([Co(phen)(H2O)4]2Cl, [Co(phen)(bpy)(H2O)2]2Cl2 and [Co(phen)(bpy)(H2O)2]2ClO4) 2 were synthesized from CoCl2, 1,10-phenanthroline and 2, 2’-bipyridine. The synthesis was checked using halide test, conductance measurement, and spectroscopic (ICP-OES, FTIR, and UV/Vis) analysis. Their in vitro antibacterial activities were also investigated on two Gram-positive (Staphylococcus aureus (S. aureus) and Staphylococcus epidermis and two Gram-negative (Escherichia coli (E. coli) and Klebsiella pneumoniae (K. pneumoniae)) bacteria. The complexes showed wide-range better activities against S. aureus, E. coli, and Staphylococcus epidermis Its activity index -35%,0.82% and -8.6% in Gentamycine respectively, -29%, 6.52% and -8.5% respectively in Contromozazole . The result indicates that the complexes had increased activity when compared with the free ligand. Therefore, the complexes may be considered as potential antibacterial drug candidates provided they passed the cytotoxicity investigations. Keywords: Co (II) complexes, 1, 10-phenanthroline, 2, 2-bipyridine, antimicrobial activity