The vapor liquid equilibrium (VLE) data for ternary systems (methane + decane + hexadecane) have been determined using a designed pressure volume temperature (PVT) apparatus. Three different (decane + hexadecane) binary mixtures were prepared, and the solubility and phase equilibria of three prepared mixtures with methane at ambient temperature and different pressures from (1 to 8) MPa were studied. The phase composition and saturated liquid density and viscosity were reported for each pressure. The VLE data of the ternary mixtures were correlated using Soave-Redlich-Kwong and Peng-Robinson equations of state. The equations of state models with their best-fitted parameters of the binary systems, (methane + decane and methane + hexadecane), were used to predict the VLE data of ternary systems. Both equations of state were found to be capable of describing the phase equilibria of binary pairs and ternary systems over the range of studied conditions. The Peng-Robinson equation of state gave better predictions of saturated liquid densities than those of the Soave-Redlich-Kwong equation of state.