This study introduces a one-pot synthesis method of PdAu-Au core-shell nanoparticles using electrodeposition and displacement reaction. It was ascertained that Au and Pd atoms were well-distributed inside the nanoparticles, and Au shell was successfully formed via displacement reaction. The influences of Au ion concentration and current density on the particle size, the atomic fractions of Pd and Au, and the surface plasmon absorption were investigated. Although the current density affected both size and composition, the concentration of Au ions only changed the composition of Au and Pd. In addition, the behavior of surface plasmon absorption according to the atomic concentration of Au was figured out. (C) 2012 The Electrochemical Society. [DOI: 10.1149/2.033301jes] All rights reserved.