An elaborate physical model is developed for the problem of two-component film evaporation. Special attention is drawn to the accurate modelling of the two-phase multicomponent flow. This includes separate description of each phase, turbulent gas flow, and thermophysical properties depending on temperature and species concentrations. Whereas the basic equations for the film flow can be treated analytically those for the gas flow have to be solved numerically by means of an accurate finite difference method. An efficient overall iteration procedure links the solutions in both phases. The evaporation of benzene-methyl alcohol mixtures in vertical tube flows for various thermal flow conditions is investigated. Results are presented in terms of local temperature, heat and mass fluxes, and Stanton numbers for heat and mass transfer. They indicate a strong influence of the mixture composition.