Phase equilibrium properties were measured with a newly designed apparatus for the mixtures of amyl alcohol + water, amyl acetate + water, and water + amyl alcohol + amyl acetate at vapor-liquid-liquid equilibrium (VLLE) conditions up to 393.15 K. The experimental data form a basis to evaluate the reliability of VLLE calculations with the phi-gamma-gamma method. It is found that the mutual solubility data can be correlated accurately by the NRTL model with temperature-dependent parameters for the binary aqueous systems over a wide temperature range. The saturated vapor compositions can also be calculated satisfactorily by Using a two-term virial equation with one adjustable binary interaction parameter. The model parameters determined from the binary VLLE data of amyl alcohol + water and amyl acetate + water and the binary,vapor-liquid equilibrium (VLE) data of amyl alcohol + amyl acetate are applicable to reproducing VLLE properties for,the ternary system of water + amyl alcohol + amyl acetate.