The prevention of wax formation under high pressure requires a reliable thermodynamic model predicting the behavior of the paraffin components at high pressure. The study on the activity coefficient models show that the predictive Wilson model is a suitable approach for the description of the non-ideality behavior of the solid phase. Also, the same study show that the liquid phase behavior is near ideal solution in the wax formation phenomena. In this work, a new and predictive thermodynamic model has been presented for the prediction of wax formation at high pressure conditions. Predictive Wilson and ideal solution models have been employed for the description of the solid and liquid phase behavior. In the proposed model, the Poynting correction term has been calculated using melting properties of pure components at reference pressure and fusion temperature at high pressure. For computerizing the model, a new correlation for calculation of fusion temperature at high pressure has been presented. For validating the new model, some experimental data have been used, which are for 120 equilibrium data points. The results of new model have 0.36 AAD% from the experimental data. (c) 2007 Elsevier B.V. All rights reserved.