The solubilities of pure and equal-molar mixed o-phthalic acid and p-aminobenzoic acid in supercritical carbon dioxide, were determined at 308.15, 318.15, and 328.15 K, and over the pressure range from 8.0 to 21.0MPa. The solubility of a given solid in a ternary system increased relative to the value of the corresponding binary system, and was in proportion to the solubility of the other solid in the ternary system. The selectivity of supercritical carbon dioxide to the solid mixture increased with the increasing temperature. The model proposed by Mendez-Santiago and Teja was applied using statistical software to correlate the solubility data of both binary and ternary systems with good results.