The generalised mixing rules of Brandani et al. [Chem. Eng. Sci. 53 (1998) 1041-1047] are extended to cubic equations of state (EOS) which represent a class of EOS that is widely used in process simulations. These mixing rules are based on activity coefficient models and a procedure that allows the use of the literature parameters for the prediction of (vapour + liquid) equilibrium is presented. Representative examples are discussed and extrapolations to high pressures are included. (C) 2004 Elsevier Ltd. All rights reserved.