We have investigated the structure and magnetoresistance of Co/Cu multilayers prepared by magnetron sputtering in a high vacuum deposition system. The results from the as-deposited multilayers show that the presence of an iron buffer layer between the glass substrate and the multilayer affects the structure of the multilayer and increases the magnetoresistance values obtained. Annealing of the multilayers also has a considerable effect on the structure and the magnetoresistance of the multilayer system.