Liquid-liquid equilibrium data for the ternary system l-butanol-l-propanol-water have been determined experimentally at 25, 50, 85 and 95 degrees C. The results obtained have been correlated simultaneously by the UNIQUAC method obtaining two sets of interaction parameters : one of them independent of the temperature and the other with a linear dependence. Both sets of parameters fit the experimental results well which is an improvement on using parameters depending of the temperature of 15%.