The vapor-liquid equilibrium (VLE) data for binary system of methane + n-octadecane at four temperatures T=(323, 348, 398, and 448)K were measured using a designed pressure-volume-temperature (PVT) apparatus. The phase composition and density and viscosity of saturated liquid phase were measured for pressures up to 10 MPa. The experimental VLE data were compared with the modeling results obtained using the Peng-Robinson and Soave-Redlich-Kwong equations of state. Two approaches, a single temperature-independent interaction parameter and temperature-dependent interaction parameter, were considered to fit the generated experimental data. (c) 2011 Elsevier B.V. All rights reserved.