Densities of pure 1-chlorobutane, pure n-hexane, and their mixtures have been measured with an accuracy of +/- 0.2 kg(center dot)m(-3), over a temperature range of (283.15 to 333.15) K and a pressure range of (0.1 to 35) MPa using a vibrating tube densimeter. The experimental densities have been correlated by the Tait equation with the temperature-dependent parameters for pure components and by the van Laar-type equation with the temperature- and pressure-dependent parameters for the solution. The excess volumes have been calculated on the basis of experimental data, and the pressure and temperature influence on this property have been discussed.