Isothermal vapor-liquid equilibrium data are presented for the R170 + n-perfluorooctane system. Measurements were performed at five isotherms ranging from 308.45 to 338.43 K and were undertaken using a "static-analytic" type apparatus, with sampling of the equilibrium phases via a moveable capillary sampler (ROLSI (TM)). The uncertainties in the measurements of temperature, pressure, and phase compositions were within 0.036 K, 0.0058 MPa, and less than 0.02 mol mol(-1) respectively. The VLE data were correlated with the Peng-Robinson equation of state, incorporating the Mathias-Copeman alpha function. The Wong-Sandler mixing rule with the non-random two-liquid (NRTL) activity coefficient model and the classical one-fluid mixing rule were used. The Wong-Sandler mixing rule represents the experimental data more accurately than the classical mixing rule. These measurements have also been compared to results obtained from isobaric-isothermal Gibbs ensemble Monte Carlo molecular simulations. Very good agreement between experiment and simulation was obtained, although systematic under-estimation of the experimental vapor compositions was observed. The simulations further validate the transferability of an existing optimum Lennard-Jones cross-parameter set. Radial distribution functions for the liquid phase were calculated and show that R170 molecules tend to cluster around each other, while the CF2 groups on n-perfluorooctane molecules show the least preference for mutual proximity. (C) 2013 Elsevier B.V. All rights reserved.