Isothermal vapor-liquid equilibrium (VLE) data are presented for (carbon dioxide + cyclopentanol) and (propane + cyclopentanol). Measurements were undertaken using a static analytic high-pressure cell at three temperatures ranging from (353.15 to 393.15) K for (propane + cyclopentanol) and at two temperatures (373.15 and 403.15) K for (carbon dioxide + cyclopentanol). The uncertainties ill the measurements of temperature and pressure are +/- 0.2 K and +/- 0.0075 MPa, respectively, and less than 2 % for composition. The binary VLE data were regressed using the phi-phi (direct) method to obtain correlated thermodynamic model parameters. Data reductions using the Peng-Robinson cubic equation of state with the Stryiek-Vera alpha function, along with the Wong-Sandler mixing rule incorporating the NRTL activity coefficient model, satisfactorily represented both systems for all the Measured isotherms. All the measured data sets were tested for thermodynamic consistency. The two tests used were the Chueh, Muirbrook, and Prausnitz area test and, probably the most regorous and theoretically correct of all, the Christiansen and Fredenslund test. The results Suggest that the data are consistent. For (propane + cyclopentanol), the latter test indicated a small bias in vapor composition for the 353.15 K isotherm. Henry's constants were also Computed for both systems from the measured experimental data by application of the Krichevsky-Illinskaya equation.