The solubilities of benzoic acid in supercritical CO2 with pure and mixed cosolvent were measured at pressures from 8.0 to 23.0 MPa and 328.15 K for pure cosolvent, and 308.15, 318.15 and 328.15 K for mixed cosolvent. The experiments were carried out by using a flow-type phase equilibrium apparatus. The effect of cosolvents, ethyl acetate, ethanol and ethyl acetate + ethanol (molar ratio 1:1) was studied at the concentration of 2.0 mol%. The results show that the solubility enhancement follows the order: ethanol > ethyl acetate + ethanol > ethyl acetate. The measured solubilities were correlated using a modified Chrastil equation, and the calculated results are in good agreement with the experimental data. (C) 2004 Elsevier B.V. All rights reserved.