For the prediction of the condensation behavior of natural gas, one has to select an equation of state (EoS) which will be accurate in the temperature and pressure range of interest (10 < P/bar < 70 bar and 250 < T/K < 310). Another requirement of the selected EoS is that it easily can be adapted to a characterization procedure for the heavy-end fraction. For that purpose, two equations were tested : the Peng-Robinson (PR), which is one of the most applied cubic EoS, and the simplified-perturbed-hard-chain theory (SPHCT) equation, which is one of the simplest EoS based on sound statistical mechanical principles. In the underlying study, their predictive capabilities for the prediction of saturated vapor pressures of pure compounds and vapor/liquid equilibrium pressures for binary mixtures are compared. Only components present in natural gas are considered. In addition, new pure-component parameters for the SPHCT EoS for n-alkanes are evaluated. Also a method to find the characteristic energy for non-n-alkane molecules is proposed in this study. This study revealed that the PR EoS predicts more accurately the liquid phase composition, whereas the SPHCT EoS is superior for the gas phase prediction, especially for asymmetric binary mixtures. It was concluded that, with respect to the purpose of this study, both EoS, when used with optimum binary interaction parameters, have an equivalent descriptive accuracy. Therefore, the simpler PR EoS was preferred to describe natural gas mixtures.