Vapor-liquid equilibrium data for three ternary systems of acetone-ethanol-N,N-dimethyl formamide (DMF), ethyl acetate-water-DMF and acetone-chloroformethyl acetate, and for four binary systems of DMF-ethanol, acetone, water and ethyl acetate have been observed at atmospheric pressure. Wilson parameters of these systems were determined. Satisfactory Values for vapor-liquid equilibrium of ternary system may then be obtained by use of the Wilson parameters obtained from binary system data.