The solubilities of (m(1) NaCl + m(2)CrCl(3))(aq) and (m(1)KCl + m(2)CrCl(3))(aq) where m denotes molality have been determined at T = 298.15K. In the sodium system, only the crystallization of the simple salts NaCl(s), and CrCl3 - 6H(2)O(s) have been established. In the potassium system, in addition to the simple salts, a new double salt with composition 2KCl . CrCl3 . H2O also crystallizes from saturated ternary solutions. The ternary solutions have been simulated thermodynamically at T = 298.15 K using the Pitzer model. The necessary thermodynamic functions (binary and ternary ion-interaction parameters, thermodynamic solubility products) have been calculated and the theoretical solubility isotherms plotted. A very good agreement is found between calculated and experimental solubility isotherms. The standard molar Gibbs energies of formation Delta(r)G(m)(0) of solid phases crystallizing in the systems under consideration have been determined from theory. (C) 2003 Elsevier Science Ltd. All rights reserved.