The solubility of sodium sulfate in the concentrated sulfuric acid + methanol system was determined at temperatures of (273, 293, 303, 313, and 323) K. The saturation densities were also determined. The solubility increased with increasing temperature until about 323 K. When the result of this study was compared with an earlier study(7) of solubility for the sodium sulfate + water + aqueous methanol system, the solubility values of the present system were greater at all comparable temperatures. This may be due to the fact that '' like dissolves like ''. In this case, the SO42- anion is common to both sulfuric acid and sodium sulfate, whereas in the former study, it is not. Moreover, compounds containing the SO42- anion are known to be less soluble in water.