It has been shown that a large number of triazole derivatives are biologically active as bactericidal agents. Certain metal complexes of these derivatives show an enhanced activity. Therefore two triazole derivatives (thiolo and acetylenic), in additions to a new ester derivative have been chosen to prepare a series of new metal complexes. The reaction of (LI) (3-mercapto-4-allyl-5-phenyl-4H-l,2,4-triazole) with [(Hg(II), Au(IJI), Pt(IV), Cd(II), Pd(II), Zr(IV), Zn (II), Cu(II), Co(H), Fe(III), Cr(III), and VO(II)] ions show to give the complexes: - [Hg(LI)2].1.5C2H5OH, [Au(LI)2]Cl.H20, [Pt(LI)4].2H2O, [CdLIClH2O].4H2O, [Pd(LI)4].4C2H5OH, [Zr(LI)2](NO3)2l [ZnLIClH2O].2C2H5OH, [Cu2(LI)2 C12].H2O , [Co(LI)2].H2O , [Fe LI (H20)2 (N03)2].6H20, [Cr LI C12 (H2O)2].H2O and [VO(LI)2].3C2H5OH and the reaction of (LII)[3-(2-propynyl) thio-4-allyl-5-phenyl-4H- 1,2,4- triazole] with [Hg(II), Au(III) and Ag(I)] ions gave the following complexes:- Hg2 LII C14 H2O , AuLIICl3 and [Ag LII].3C2H5OH and finally the reaction of LIII (3-thio carboxyphenyl-4-allyl-5-phenyl- 4H-l,2,4-triazole) with [Hg(II), Au(III), Cd(II), Cu(II) and Fe(III)] ions gave the following complexes:- [Hg2 (LIII)2 C14].2C2H5OH, [Ail (LIII)2]C1, [Cd LIII C12]. C2H5OH, [Cu2 LIII (H2O)5 C14].4H2O , [Cu2 (LIII)2 C12].6 C2H5OH and Fe2 LIII (OH)2 (N03)4 (H2O)2 All the ligands and their metal complexes were characterized using the appropriate techniques, which include, melting points, i.r. spectra, uv-vis., elemental analysis, magnetic susceptibility and the electrical conductivity measurements. According to the data obtained, the structural formulae for all complexes were suggested. The three ligands exhibit different coordination behaviour with the metal ions, this depend on the nature of the donor groups in each ligand and the type of metal ion. The ligands and their complexes were screened for their antibacterial activity against gram negative (Escherichia coli) and gram positive (staphvlococcus aureus) bacteria. Using standard anti-biotics far comparison, a number of the new complexes were more active than their corresponding ligands.