The successful electro-synthesis of a composite made of polythiophene nano-wires and platinum nano-particles is reported. The nano-wires were prepared on a Pt electrode previously modified with a mesoporous silica thin film. The silica film modified electrode was also prepared and characterized by electrochemical means. For the electro-polymerization the working solution was 1.0×10−3 molL−1 thiophene and 1.0×10−1 molL−1 tetrabuthylammonium hexafluorophosphate in anhydrous acetonitrile. The nano-structured electrode was characterized and subsequently modified by dispersing platinum nano-particles employing an experimental method based on polymer doping properties. Also, electro-catalytic activity of the composite with respect to formic acid electro-oxidation was verified. The results were outstanding and compare well with those obtained employing a bare polycrystalline platinum electrode. The nano-wire deposit and the composite were analyzed by transmission electron microscopy, confirming the expected morphology and crystalline degree. All these results are of the utmost importance since only simple electrochemical preparative methods were utilized, allowing more control of the process and lowering production cost.