Progress is reported towards the development of a comprehensive model useful in process design and optimisation of CdS thin-film growth. Model equations are developed for the temporal variation of reactants concentrations as well as of the precipitating solid phase, both in the bulk and on the substrate. A combination of possible elementary mechanisms is employed and the resulting system of equations is solved numerically. Computational results show that the model is consistent with available experimental data, on film thickness evolution, suggesting that it may prove very useful for optimising the CBD process with respect to its design variables. To conclude the presentation, some aspects of the deposit morphology at the early stages of its growth are discussed. It appears that these first stages determine the properties of the final film.