Based on a linearized kinetic equation (the McCormack model), the theory of motion of binary gas mixtures in a plane channel owing to the temperature, concentration and pressure gradients is established. As a result, the relationships are obtained showing the dependence of the thermal, diffusional and numerical mean fluxes on the Knudsen number and concentration of the components. The calculations are carried out for the mixtures He-Ar, He-Ne, Ne-Ar with the use of three models of intermolecular potential: ‘solid spheres’, ‘Maxwell molecules’, Lennard-Jones (6–12)-potential. Based on the Prigogine theorem, the effects characteristic of gas mixtures (thermal diffusion and pressure diffusion separation of mixtures, diffusional baroeffect, thermomolecular pressure difference) are considered. The theory is compared with experiment.