In this work, experimental liquidliquid equilibrium data for three pseudoternary systems containing {refined sunflower seed oil + aldehyde + anhydrous ethanol} were determined at a temperature T of 298.15 K with u(T) = 0.05 K and atmospheric pressure. Binodal curves and tie line compositions are reported for n-hexanal, 2-nonenal, or 2,4-decadienal as solutes. The nonrandom two-liquid(1) and universal quasichemical(2) models satisfactorily correlated experimental tie line data. OthmerTobias(3) and Hand(4) methods attested the quality of experimental data. Further, the predictive capabilities of four versions(5-9) of the UNIFAC(10) method were analyzed.