In this study, experimental tie-line data for the ternary system containing water, citric acid, and 1-decanol were measured at various temperatures (298.2, 308.2, 318.2, and 328.2 K) and atmospheric pressure (101.3 +/- 0.4 kPa). The reliability and consistency of the liquid liquid equilibrium experimental data were evaluated by the Othmer-Tobias and Hand equations. The distribution coefficients and separation factor of this system for solvent capability were calculated. The maximum of separation factor for 1-decanol as solvent was obtained as 4.25 at 298.2 K and decreases with increasing temperature and citric acid concentration. Finally, by using the genetic algorithm method, interaction parameters of the NRTL thermodynamic model were measured for these experimental data. The values of the parameters of this model were evaluated with the root-mean-square deviation (rmsd) method. The average rmsd value between the experimental and calculated mass fraction was 0.1984% for the NRTL model. The rmsd values demonstrate that the NRTL model is suitable for description of phase behavior and can be applied to this system.