Alkali and tetraalkylammonium iodides, generally used as electrolytes in analytical electrochemistry, were found to corrode platinum surfaces submitted to cathodic polarization. This phenomenon seems to be very general when aprotic dipolar solvents, carefully dried, are used. Thus, in dimethylformamide a slow reduction step implying platinum metal is observed and appears strongly dependent on the nature of the electrolyte cation. The corrosion process seems to be due to the concomitant insertion of cations and salts which leads to platinum clusters. Electroanalysis shows that corrosion (weight loss, surface holes and grain joins) may depend on both the potential applied to the metal and iodide salt concentration.