A finite difference model describing simultaneous heat and mass transfer in a hybrid liquid desiccant cooling system is presented in this paper. This type of system provides cooled and dehumidified air by a combination of a packed absorber tower and a conventional vapour compression system. The model will allow the prediction of the rate of condensation in the dehumidification tower and the evaporator of the vapour compression system, the conditions of the air and liquid desiccant leaving the tower, the conditions of the air leaving the evaporator, and other important parameters. The mathematical model results were validated with existing experimental data for a similar system with an uncertainty of 10.5% for the total rate of condensation and 0.8 degrees C for the evaporator air exit temperature. Copyright (c) 2005 John Wiley & Sons, Ltd.