The main goal of this study was to measure the solubility of mefenamic acid in supercritical carbon dioxide (SC-CO2) at pressures and temperatures range of 16-40 MPa and 308.15, 318.15, 328.15 and 338.151<, respectively. The obtained results revealed that the mole fractions were varied in the range of 8.31 x 10(-5)-5.98 x 10-3 under the different conditions. The obtained results were correlated with four empirical correlations including Chrastil, Mendez-Santiago-Teja (MST), Bartle and Kumar and Johnston (K-J) models. The optimized parameters of these correlations were obtained by the graphical regression. The calculated results show a good consistency between the measured and calculated solubilities for Chrastil, MST, Bartle and Kumar and Johnston models with average absolute relative deviation percent (AARD%) of 5.84%, 3.93%, 4.79%, and 5.20%, respectively. In addition, experimental results were modeled with two equations of state including the Esmaeilzadeh-Roshanfekr (ER) and Peng-Robinson (PR) EoSs which their binary interaction parameters, ku and I, were optimized by the differential evolution (DE) method. DE is a very simple population based stochastic function minimizer which is very powerful at the same time. The estimated solubilities show maximum AARD% of 21.25% and 30.56% and minimum AARD% of 3.54% and 6.81% were found for the ER and PR-EOS's, respectively. (C) 2011 Elsevier B.V. All rights reserved.