The total vapor pressure of liquid mixtures of xenon and cyclobutane has been measured at 182.34 K (the triple point of dinitrogen oxide) and at 195.49 K (the triple point of ammonia), as a function of composition. The mixtures show small positive deviations from Raoult's law at both temperatures. The liquid densities were also measured at 182.34 K. Both the excess molar Gibbs energy (G(m)(E)) and the excess molar volume (V-m(E)) were calculated from the experimental data. For the equimolar mixture G(m)(E) = 9.9 J mol(-1) at 182.34 K, G(m)(E) = 24.0 J mol(-1) at 195.49 K, and V-m(E) = -1.077 cm(3) mol-1 at 182.34 K. The excess molar enthalpy (H-m(E)) was estimated from the temperature dependence of G(m)(E) and found to be -185 J mol(-1). The results were interpreted by using the statistical association fluid theory and compared with those for the linear analogue system (xenon + n-butane).