A fully predictive mathematical model based on first principles of heat and mass transfer as well as vapor-liquid equilibrium was developed for desalination application via tubular direct contact membrane distillation. The model took into account the temperature and the effect of concentration polarization. The model＇s prediction in terms of distillate flux were validated with previously published experimental data for such process parameters as saline water and cooling water flow rates and temperatures, and feed salt concentration. The model＇s results agreed well with previously published experimental and theoretical work.