Thickness, density, surface and interface roughness of Al-Co-Ni single and multiple layer films deposited by high-vacuum e-beam evaporation on different substrates were investigated using X-ray reflectivity (XRR). The resolution limits of the XRR technique and the reason of the deviation from the deposition parameter were discussed. Al-oxide, Co-oxide surface and Si-oxide interface layers could be deduced from the fit of the measured reflectivity curves. The density of layers in Al, Co/Al, Al/Co and Co/Ni/Al films was almost similar to their bulk values. The surface and interface roughness of the films deposited on quartz substrates were found to be higher than for the films deposited on Si(100). The resulting thicknesses of the layers are consistent among each other, but higher than the specified values chosen before deposition. It has been demonstrated that the resolution of the XRR is also sensitive to density difference across the layers in addition to roughness. The thickness resolution of XRR is limited to a total layer thickness of 220 nm for this kind of specimen. © 2005 Elsevier Inc. All rights reserved.