The electrochemical oxidation of benzoic acid (BA) has been studied on boron-doped diamond electrodes on acid medium by cyclic voltammetry and bulk electrolysis. The results showed that in the potential region where the supporting electrolyte is stable, reactions occur, resulting in the loss of activity due to electrode fouling. Electrolysis at high anodic potentials in the region of electrolyte decomposition causes complex oxidation reactions that lead to incineration of BA. There is no indication of electrode fouling. Salicylic acid, 2,5-hydroxybenzoic acid and hydroquinone have been detected at trace level by HPLC as soluble products during the electrolysis of BA.