Densities for binary mixtures of (acetone + o-xylene, + m-xylene, and + p-xylene and 2-butanone + o-xylene, + m-xylene, and + p-xylene) have been determined at 298.15 K, and excess molar volumes have been derived. Surface tensions of these binary mixtures have been measured at 298.15 K by the pendant drop method, and the values of the surface tension deviation for these mixtures were also calculated.