The square-well-fluid thermodynamics and liquid structure derived from Barker-Henderson's perturbation theory, including a truncation correction, are used within a SAFT (statistical associating fluid theory) framework to develop an equation of state for real chain fluids. The pure-alkane vapor pressure, liquid density, critical region, and heat capacity are found to be more accurate than those correlated with other equations of state, and the parameters are well behaved and, hence, easy to estimate. Also the mixture properties are found to be well represented without much fitting.