Isothermal vapor-liquid equilibria were measured for the binary systems, acetone-methanol, acetone-ethanol, acetone-benzene, ethanol-benzene, and methanol-benzene, at 15 ℃, 25 ℃ 35 ℃, 45 ℃, and 55 ℃ using the total pressure method. Vapor compositions were obtained by the Wilson equation and the Redlich-Kister equation, minimizing the objective function ∑（P_exp-P_cal）_i by a nonlinear regression method. For these systems, isobaric vapor-liquid equilibria were estimated by cross plotting isothermal vapor-liquid equilibrium data which were obtained from the total pressure method. Also isobaric vapor-liquid eguilibria in the ternary systems of acetone-benzene-ethanol, acetone-methanol-benzene were estimated from the results for the corresponding binary systems. The predicted isobaric data were found to be in a good agreement with the experimental data taken at 760 mmHg.