Differential pulse(d. p.)polarography has been used to study the simple and mixed ligand complexes of 1, 3 diaminopropane (DAMP) and phthalate(PHLT) with Cd(II) at constant ionic strength (u= 1.0 M NaNO3) at 25°C The overall formation constants of simple and mixed complexes were calculated. The reduction of the simple and mixed species is reversible and diffusion controlled. The postive values of the mixing constants for the mixed-ligand complexes indicate that the mixed-ligand complexes are more stable than simple binary complexes. The equilibria between the various mixed-ligand species in the solution and their equilibrium are given.