Quantitative indication of a complex formation comes from the estimation of the stability or formation constants characterizing the equilibria corresponding to the successive addition of ligands. Paper ionophoresis is used for the study of equilibria in binary complex systems in solution. This method is based on the movement of a spot of metal ion in an electric field at various pH of background electrolyte. A graph of pH versus mobility was used to obtain information on the binary complexes and to calculate its stability constants. At an ionic strength of 0.1 M and 35ºC, the stability constants of ML and ML2 complex species of certain metal ions copper(II), manganese(II), and uranyl(II) with - α-Aminobutenoic acid and hydroxyproline were determined. The stability constants of ML and ML2 complex species of metal(II)-α-aminobutenoic acid and metal(II)– hydroxyproline were found to be [(7.70 ± 0.03, 6.38 ± 0.11), (3.19 ± 0.02, 2.07 ± 0.09), (7.32 ± 0.05, 5.49 ± 0.12)] and [(8.23 ± 0.05, 7.05 ± 0.03), (3.74 ± 0.06, 3.15 ± 0.09), (7.39 ± 0.11, 6.67 ± 0.02)] for copper(II), manganese(II) and uranyl(II) complexes, respectively. The present paper electrophoretic technique has proved to be useful in deciding whether a complex system is formed or not, and if it is formed its stability constants can also be determined.