A thermodynamic structure has been developed for the calculation of the cloud point, quantity, and composition of wax precipitates over a wide range of temperatures. The model is based on a combination of the concepts of ideal solution and multiple solid phase formation, and uses cubic equations of state. The experimental systems used to show the predictive capacity of the model have varied characteristics: synthetic systems of continuous series of heavy alkanes, discontinuous series ("bimodal"), and petroleum fluids with non-defined fractions as C20+, C30+, etc. The present treatment insures thermodynamic consistency and is simple to compute, minimizes adjustable parameters, and overcomes some limitations of previous models. The calculated results show smaller deviations from experimental data than other models. (c) 2006 Elsevier B.V. All rights reserved.