The anodic methoxylation of formaldehyde dimethylacetal (FADMA) to trimethylorthoformate (TMOF) in basic methanol was investigated on boron-doped diamond (BDD) electrodes. Cyclic voltammetry and preparative electrolysis have shown that FADMA is electrochemically inactive in the solvent stability region; nevertheless FADMA can be oxidized in the potential region of methanol oxidation. A reaction scheme involving intermediates of methanol oxidation (methoxy radicals) has been proposed.