The vapor-liquid equilibrium data for each system composed of acetone, methanol, 2-propanol, and 1-propanol at the isobarlc condition of 1 atm are presented. The experimental data of the binary systems were used to calculate the binary parameters of the Wilson equation. These binary parameters have been used to calculate vapor-phase compositions and boiling points of related ternary and quarternary systems. Calculated vapor-phase compositions and boiling points have been obtained very close to the experimental data for each system investigated. © 1990, American Chemical Society. All rights reserved.