The (p,V m ,T) behaviour of (octane+1-chlorobutane) was measured at the temperatures (298.15, 308.15, 318.15, and 328.15)K and over the pressure range (0.1 to 40MPa) with an accuracy in density of +/-1.10 - 4 g.cm - 3 . An apparatus for (p,V m ,T) measurements of liquids and liquid mixtures whose main part is a high-pressure vibrating-tube densimeter working in a static mode was used for the measurements. Excess molar volumes were calculated from the data and fitted to the Redlich-Kister equation.