The solubilities and complex phase equilibria for the system of MnSO4 center dot 4H(2)O+MgSO4 center dot 7H(2)O+H2O+CH3OH were determined at the temperatures 291.2 and 301.2 K over the methanol mole fraction range of 0.00-0.12. The solubility data were used for modelling with the modified extended electrolyte non-random two-liquid equation. The salting-out effect Of MgSO4 and methanol on the solubilities of two manganese salts (MnSO4 center dot H2O and MnSO4 center dot 4H(2)O) are represented in the several thermodynamic figures as a function of temperature. The solventing-out effect was stronger than the salting-out effect, which results in a decrease of the solubilities of manganese, salts even though the solubility of MnSO4 center dot H2O decreased and solubility Of MgSO4 center dot 4H(2)O increased as temperature increased. Crown Copyright (c) 2008 Published by Elsevier B.V. All rights reserved.