Vapor-liquid equilibrium (VLE) data were measured for the ternary 2-butanone(1) + benzene(2) + n-octane(3) system using an isoteniscope of our design over the temperature range (298.05 - 323.10) K. The data are examined on the basis of the DISQUAC group contribution model. In terms of DISQUAC, the mixture is characterized by three types of : contact : aliphatic/ketone, aliphatic/benzene and benzene/ketone. Only for the latter, the interchange coefficients are not available in the literature, and are estimated in this work using VLE and excess enthalpy data for the binary 2-butanone + benzene system. Applying the same parameters to the ternary system under study, DISQUAC yields total pressures values which are 3% lower than the experimental results.