Densities and excess molar volumes for the six binary mixtures containing 2,2,4-trimethylpentane + 1,2-dichloroethane, + 1,1,1-trichloroethane, + 1,1,2,2-tetrachloroethane, + 1,2-trans-dichloroethylene, + trichloroethylene, or + tetrachloroethylene have been determined at 298.15 K and atmospheric pressure using an Anton Paar density meter. The experimental values have been correlated by the Redlich-Kister equation and the parameters have been evaluated by least-squares analysis. For all mixtures, the V(E) values, whose maximum ranges from -0.38 up to 0.65 cm3 mol-1, decrease with increasing number of chlorine atoms in the molecule. This volume effect is discussed qualitatively in terms of the molecular interactions.