A review is presented of the selective heterogeneous processes that occur on the interface of two media when exposed to laser radiation. These processes can be used for selective chemical reactions and for laser separation of isotopes. Their main attraction is the relatively low activation energy, so that IR laser radiation can be used to act effectively on the surface properties. The review deals with: separation of molecules having different isotopic composition involving adsorption, selective laser-stimulated diffusion, resonant control of surface processes by laser radiation, laser chemistry on the interface of two phases or of two liquids. Experimental results are reported and interpreted.