Abstract: The predictions of ternary liquid -liquid - alkanol equilibria of 10 water - alkane -alkanol systems were made from the activity coefficients of three components in miscible regions measured with Gas Chromatographic Headspace Analysis method. The UNIQUAC parameters were fitted to the measured activity coefficients and then used to predict ternary liquid - liquid equilibria. The mean square root errors were compared with those in literature and the results were quite be satisfactory. For the liquid -liquid equilibrium data of the cy-clohexane - 1-butanol -water system which was measured in this work the results of prediction are also good.