In this study, we determined the stability of some fully N-methyl substituted polycation-inorganic polyanion complexes by potentiometric measurements at t = 25 degreesC. As for other previously studied similar systems, the stability of ALH(r) species (A = amine; L = inorganic polyanion; r = 1, 2, ... m, with m greater than or equal to n, n = maximum protonation degree of the amine) is a function of the charges involved in the formation equilibrium. The basicity of the polyanion also plays a fairly significant role. The stability of these species is compared with that of analogous species of unsubstituted amines and with that of polyammonium-carboxylate complexes. Simple predictive stability relationships are given.