We report on the characterization by X-ray scattering and atomic force microscopy of laterally nanostructured Pb/Ge multilayers in which a diffraction grating is introduced by a periodic square lattice of submicron holes ('antidot lattice'). Experimental low- and high-angle specular X-ray scattering data reveal the layered structure and interface roughness and using model calculations, a slightly increased structural disorder within the Pb layers is observed, while still a good multilayer periodicity is maintained. Atomic force microscopy and diffuse X-ray reflectivity provide information about the lateral grating periodicity. It is shown that by combining atomic force microscopy and X-ray scattering, detailed information about the internal structure and the geometrical configuration of these metallic mesoscopic systems can be obtained. (C) 2000 Elsevier Science S.A. All rights reserved.