Cu/Ag multilayers with individual layer thicknesses between 3 and 50 nm produced by DC magnetron sputtering have been studied by cross-sectional transmission electron microscopy (XTEM). The aim of this work was to study the development and morphological properties of the columnar structure and the evolution of the interface morphology in multilayer systems. The column width and the wavelength of the interface waviness increased with the multilayer period. The increase in the column width saturated at 30 nm multilayer period. In the shea period range (below 30 nm) and in the substrate-near part of the 92 nm period film the wavelength of interface waviness had the size of columnar structure. Far from the substrate in the 92 nm period film the wavelength of waviness increased further having about two times larger values than the crystalline column width.