Liquid-liquid equilibria for the system naphtha reformate-dimethyl sulphoxide were determined in the temperature range from 298 K to 323 K and for three solvent to feed ratios. The experimental data were compared with the values predicted by the UNIFAC group contribution model. It was shown that the UNIFAC model was capable of predicting the concentrations in this multicomponent system with an overall RMSD of 1.58 mol.%.