The chelates of some arsenazo compounds derived from 1- and 2- naphthol and 1-hydroxy-2-naphthoic acid as ligand with Sc(III), Y(III), La(III), Th(IV), and uranyl(II) ions have been investigated in solution using spectrophotometric and conductometric titration methods. The studies revealed the formation of Ml and ML2 complexes. The solid chelates have been characterized by chemical analysis, thermal methods (DTA and TGA), IR, and electronic spectra.