Absorption by means of triethylene glycol is one of the most popular methods for natural gas dehydration. In spite of this popularity, thermodynamic modeling of the system TEG-water is still rather inaccurate, especially with regard to systems at high temperature and high TEG concentration, which are typical conditions in the glycol regeneration unit. Available experimental data were selected and correlated by means of a thermodynamic model based on the Peng-Robinson equation of state. Obtained results show that the model provides a good representation of experimental data and leads to a reliable prevision on typical plant data. Because of its accuracy and simplicity, the proposed model is a valuable tool for the design of natural gas dehydration processes.