Benzoic acid solubility has been measured in pure water and in the binary mixtures containing different solvents including water, N,N-dimethylformamide (DMF), ethanol, or 1,4-dioxane. The experiments were carried out employing the cell used in Oliveira's dissertation. The temperature dependence of the solubility of an acid in two solvents could be evaluated. There was similar influence of the temperature in the solubility of benzoic acid in mixtures of water + DMF and water + 1,4-dioxane. An increase in acid solubility was observed with temperature in all mixtures. Addition of more ethanol in water favors the solubilization of benzoic acid.