The truncated Perturbed-Chain Polar Statistical Associating Fluid Theory (tPC-PSAFT) is applied to a number of different mixtures, including binary, ternary and quaternary mixtures of components that differ substantially in terms of intermolecular interactions and molecular size. In contrast to most other SAFT versions, tPC-PSAFT accounts explicitly for polar forces. Three pure-component parameters are required for non-polar and non-associating compounds, two additional parameters characterize the association contribution and one parameter is needed to account for polar interactions. The experimental dipole and/or quadrupole moment and/or polarizability of the component are used to calculate polar interactions. Using a temperature-independent interaction parameter k(ij) for each binary system, tPC-PSAFT provides accurate prediction of multi-component phase behavior over a wide range of conditions. (C) 2007 Elsevier B.V. All rights reserved.