The stability constant of mixed ligand complexes of Cd(II) with aspargin and some bicarboxylic acids (Malonic Acid, L(+)-Tartaric Acid, DL-Malic Acid and Maleic Acid) have been determined electrochemically. The stepwise formation constants of simple Cd-Aspargin and Cd-Bicarboxylic acids have been investigated by Deford and Hume's method. Then the mixed ligand complexes of Cd with aspargin and bicarboxylic acids have been studied by the method of Schaap & McMasters. The mixing constant (KM) and stabilization constant (KS) were measured for the comparison of the simple and mixed ligand complexes. The positive value of mixing constants and stabilization constants show that the ternary complexes are more stable than the binary complexes.