This paper presents the behavior of 20 wt.% PtSn supported catalysts as anodes for direct ethanol fuel cell (DEFC), which is fed with an aqueous ethanol solution. PtSn nanoparticles with different Pt:Sn ratios (1:1 and 3:1) were supported on carbon black and carbon nanofibers. Physicochemical characterization showed high particle dispersion onto the carbon supports and similar particle size (around 4.0 nm). XRD analysis indicated the presence of SnO2 and similar lattice parameter for PtSn (1:1) to those of pure Pt3Sn1. Prepared catalysts were electrochemically studied in acidic medium by carbon monoxide (CO) stripping voltammetry, cyclic voltammetry, lineal sweep voltammetry and chronoamperometry in three-electrode cell experiments. In addition, cell voltage vs. current density curves were recorded in a DEFC. It was found that PtSn anodes exhibit good activity toward ethanol electrooxidation in half-cell experiments under fuel cell relevant conditions. Specifically, PtSn supported catalysts on carbon black showed higher catalytic activity compared to those supported on carbon nanofibers. The low activity for ethanol adsorption/deprotonation and C-C cleavage appear as the main causes for the low performance for ethanol oxidation reaction on catalysts supported on carbon nanofibers. A similar behavior was observed in single fuel cell experiments. (C) 2014 Elsevier B.V. All rights reserved.