Liquid-liquid equilibrium (LLE) data were measured at 298.15K and atmospheric pressure for six ternary systems: n-hexane+benzene+sulfolane,n-hexane+toluene+sulfolane,n-hexane+xylene+sulfol ane,n-octane+benzene+sulfolane,n-octane+toluene+sulfolane,n-octane+xylene+su lfolane;threequaternarysystems:n-hexane+n-octane+benzene+sulfolane,n-hexane+ benzene+toluene+sulfolaneandn-octane+toluene+xylene+sulfolane;onequinarysyst em:n-hexane+n-octane+benzene+toluene+sulfolane. The equilibrium data of ternary systems were used to regress interaction parameters in non-random two-liquid (NRTL) equation. These parameters were directly used to predict equilibrium data of quaternary and quinary systems. The predicted data are in good agreement with experimental data.