Complexation reactions of nitrilotriacetate (NTA) and penicillamine with $Cu^{2+}$ and $Co^{2+}$ have been studied in solution phase using paper electrophoresis technique. The stability constants of the complexes Cu(II)-nitrilotriacetate-penicillamine and Co(II)-nitrilotriacetate-penicillamine have been found to be $6.64{pm}0.03;and;5.86{pm}0.05$ (logarithm stability constant values), respectively at 35$^{circ}C$ and ionic strength 0.1 M.