Electrodeposition of Co-Ag/Ag multilayers along with their giant magnetoresistance (GMR) was investigated. The electrodeposition process was optimized for both minimizing the dissolution of the Co layer and achieving a high magnetoresistance. Structural analysis of Co-Ag/Ag deposits revealed that silver has an fcc structure, whereas cobalt crystallizes in the hcp structure. No solid solution of Co and Ag was detected. The X-ray diffraction study did not show any satellite reflection. A GMR of the order of 0.5% and 2% could be observed at room temperature and at 20 K, respectively, with both superparamagnetic and ferromagnetic GMR contributions throughout the temperature range studied. (C) 2009 Elsevier B.V. All rights reserved.