Three sets of Co/W bilayers with varying Co and/or W layer thickness were prepared by d.c. magnetosputtering technique. The magnetic properties of Co/W bilayers have been investigated using ferromagnetic resonance (FMR) and vibrating sample magnetomete. Specular X-ray reflectivity and high angle X-ray diffraction were used to characterize the structure of the deposited samples. The saturation magnetization of Co increased with Co thickness but was smaller than that of bulk hcp Co. The larger interface roughness and FMR line-width for the thinner Co/W films indicate the inhomogeneity of Co and/or W layers.