The electrooxidation of ethanol (C2H5OH) is studied on the surface of platinum (Pt) electrode in 1.0 М aqueous solutions of methanesulfonic acid (CH3SO3H). It is found that the complete displacement of adsorbed hydrogen from the Pt surface in the potential region of 0.03–0.4 V (r.h.e.) occurs at the ethanol concentration 2.0 М C2H5OH. In the anodic scanning region, three ethanol oxidation waves are observed in the potential regions E: 0.8–1.1, 1.15–1.45, and 1.5–1.8 V (r.h.e.). The analysis of products of preparative electrolysis in the aforementioned potential regions carried out by the methods of molecular (UV, near IR-Fourier and Raman) spectroscopy has shown that the first wave of ethanol oxidation corresponds to the formation of acetaldehyde, the second wave corresponds to acetic acid, and the third wave is associated with the formation of carbon dioxide (СO2). In the reverse cathodic scan, the anodic wave with the peak at 0.55 V (r.h.e.) appears which is associated with the direct oxidation of ethanol to СO2. It is assumed that the mechanism of ethanol electrooxidation on Pt in 1.0 М СH3SO3H is analogous to that realized in sulfuric acid solutions.