We report on the fabrication of layer-by-layer (LbL) films of PAMAM dendrimers incorporating platinum nanoparticles (Pt-PAMAM) alternated with poly(vinylsulfonic acid) (PVS). Pt-PAMAM structures were obtained via chemical reduction of H2PtCl6 in the presence of PAMAM, using formic acid as reducing agent. An average particle size of 3 nm was estimated using the Scherrer equation with the X-ray diffractograms in multilayer films, which was confirmed with transmission electron microscopy (TEM) for a Pt-PAMAM layer. The formation of Pt nanoparticles was monitored with UV–Vis spectroscopy by measuring the decrease in the band intensity at 375 nm, assigned to the electronic absorption from ions. These LbL films were proven fully tolerant to methanol oxidation for potentials below 1.0 V. As a proof of principle, we show that the electrochemical response for the Pt-PAMAM LbL films is characteristic of platinum, regardless of the presence of methanol in the electrolytic solution. The discovery of a methanol-tolerant electrode in Pt-PAMAM LbL films may represent a major breakthrough for further developments in methanol fuel cells, since methanol crossover through the membrane is one of the most important drawbacks of direct-methanol fuel cells.