The problem of heat and mass transfer enhancement of liquid film condensation by covering a porous layer on one of channel vertical plates has been numerically investigated. The liquid film falls on one plate of a vertical channel under mixed convection. The wetted plate is covered with a thin porous layer and externally subjected to a uniform cooling heat flux while the second plate is dry and isothermal. The effects of porosity, porous layer thickness and the ambient conditions on the heat and mass transfer performance and on the liquid film condensation have been examined in detail. The numerical results show that the heat and mass transfer performance at the liquid-gas interface during the liquid film condensation is enhanced by the presence of the porous layer.