Lateral nanometer-scale control over the growth of polyelectrolyte (layer-by-layer) multilayers is demonstrated down to 40 nm, which is well below the natural size of the macromolecules in solution. Because of confinement upon adsorption, the molecules change conformation as compared with the usual, macroscopic case (see Figure). This work opens direct opportunities for transferring polyelectrolyte multilayer systems to nanotechnology.