A ternary system of methanol-ethanol-water was distilled in a packed distillation column having an internal diameter of 0.10 m. The data obtained indicated that an increase in the intermediate component concentration in the feed mixture reduces the component efficiency of the mast volatile component. The data also indicated that the influence of intermolecular interaction on the separation efficiency of the component in the mixture is significant. The results compare favorably with few reliable data in the literature.