The uranyl complexes of N,N,N′,N′-tetrakis(carboxymethyl)-2,3-diaminopropionic acid, N,N,N′,N′-tetrakis(carboxymethyl)diaminobutyric acid, N,N,N′,N′-tetrakis(carboxymethyl)ornithine and N,N,N′,N′-tetrakiscarboxymethyl)lysine have been studied by potentiometry, with computer evaluation of the titration data by the MINIQUAD program. Stability constants of the 1:1 and 2:1 metal:ligand chelates have been determined as well as the hydrolysis and polymerization constants at 25° in 0.1M potassium nitrate. Results are compared with those obtained for the uranyl complexes of the corresponding members of the series of the polymethylenediaminetetra-acetic acids. © 1987.