Liquid-liquid equilibria of the ternary system water + dodecane + 2-butyloxyethanol in the temperature range from 25.0 degreesC to 65.0 degreesC were performed at atmospheric pressure. The experimental data were correlated with the UNIQUAC model and good agreement was obtained. For the system with a three-liquid-phase-coexisting region, all six UNIQUAC interaction parameters can be numerically regressed by simply minimizing the deviation of the compositions of three coexisting liquid phases.