An acoustic technique was applied to investigate the binary critical behavior of the system CO2 + Xe. The critical line of this binary system exhibits a temperature minimum, suggesting the existence of azeotropic behavior. The compositions of the studied mixtures were chosen in order to define the minimum temperature locus (p = 6.04 MPa, T = 282.34 K and at x(CO2) = 0.3622). The results were correlated with the Peng-Robinson equation of state using conventional mixing and combining rules. Additionally, the same equation was used to correlate published data on CO2 with the five lower normal alkanes. The adjustable interaction energy and size parameters for CO2 + Xe are in line with these from CO2 + C2H6 up to CO2 + C5H12, while those for CO2 + CH4 deviate significantly.