Bimetallic Pd-Au nanostructures were synthesized in the soft templates provided by surfactant hexagonal mesophases. The nanostructures are constituted by a core rich in gold and a Pd porous shelf. The electrocatalytic activity of these nanostructures for ethanol oxidation in basic medium was compared with that of alloyed Pd-Au nanoparticles synthesized in solution. The Pd-Au alloy is active toward the oxidation of ethanol in an alkaline medium but is not durable in realizing this process. The Pd-shell-Au-core nanostructures synthesized in mesophases are promising for application in direct ethanol fuel cells as they exhibit a very good electrocatalytic activity and a high stability.