This study describes a developing laminar falling film over a vertical plate while heat and mass transfer occurs. The model accounts for a developing film thickness and uni-directional diffusion. The fluid properties are assumed to be constant, and latent heat, which is relatively large in comparison to the sensible heat, is set free at the liquid-vapor interface. Temperature and concentration profiles in the film, the development of the interface velocity, as well as the absorbed mass fluxes are presented and two different boundary conditions have been applied to the inlet of the film.