Tyrosine is indirectly involved in nerve transduction in CNS (Central Nervous System) and behaves as good chelating agent for many metal ions, because of its structure. This prompted us to carry investigations of several mixed ligand complexes forming equilibria involving tyrosine as one of the ligand with nutrient and toxic metal ions. Present piece of work describes investigation of ternary systems of Tyrosine with alanine, phenylalanine, Glycine, valine, leucine and cadmium at 35±10C at three different ionic strengths in aqueous medium. The values of proton dissociation constants of ligands and formation constants of complexes were calculated by algebraic method of Chaberek and Martell as modified by Dey et. al. pH-metric data was subjected to SCOGS computer program. Thermodynamic formation constants were obtained by extrapolating the values to zero ionic strength in log b vs.√ curve. Finally, all the systems are explained on the basis of speciation of species in entire pH range of the experiment.