Isothermal vapor liquid equilibrium data are presented for binary systems containing perfluorobutane with carbon monoxide or nitric oxide. The measurements were undertaken for both systems at three temperatures ranging from (293 to 333) K, with pressures ranging from (0.965 to 16.130) MPa. The measured data were successfully correlated via the direct method using the Peng-Robinson equation of state incorporating the Mathias-Copeman/Stryjek-Vera alpha function and the Wong-Sandler mixing rule utilizing the nonrandom two-liquid (NRTL) activity coefficient model.