An electro-Fenton treatment of a solution containing phosphorus compounds using a graphite electrode is described. Different operating conditions are tested to investigate the influence of the reagent ratio on the oxidative efficiency. Results show that electro-Fenton's reagent is able to provide a powerful conversion of the phosphorous compounds into phosphate. As hydrogen peroxide is continuously provided by the cathodic reduction of oxygen, the crucial step appears to be the iron dosage whose optimal concentration is found in the range 50 - 150 mg l(-1). Quantitative oxidation is not reached for concentration lower than 50 mg l(-1). Nonetheless, an excess of both iron and hydrogen peroxide in the bulk is found to negatively affect the oxidation yield because of the occurrence of undesired side reactions.