The influence of the catalyst used on the oxidation of an aqueous solution of phenol with hydrogen peroxide was investigated. For catalysts based on ferrous sulfate, ferric hydroxide and active carbon, the influence of stoichiometric excess of hydrogen peroxide and of the amount of the catalyst on the rate of oxidation was studied. The experiments were carried out at atmospheric pressure at 30 - 80 ^oC in a thermostated glass flask. Phenol and its oxidation products were determined by HPLC analysis: in selected samples the determination of the chemical oxygen consumption was performed by the dichromate method. Fe(II) ions seem to be the most active catalyst, followed by the Fe(OH)₃ slurries. In addition to oxidation, phenol was also adsorbed on active carbon.