An experimental study with three different heterogeneous azeotropic mixtures (ace tone/toluene/water, 1-propanol/1-butanol/water and ethanol/cyclohexane/water) has been carried out with the object to analyze the separation efficiency of three-phase distillation in a packed column. The experiments were made under total reflux in a 70 mm column packed with Sulzer Optiflow C.36. The results show the influence of the second liquid phase on the mass transfer and with that on the separation efficiency in a packed column.