Ethyl-tert-butyl ether (ETBE) was converted by hydrogen peroxide in the presence of HCL, NaCL, H2SO4 and citric acid in aqueous medium under UV radiation. The strong inhibiting effect of hydrochloric and sulfuric acids on ETBE conversion was observed. Citric and hydrochloric acids inhibited the oxidative conversion of the etheronly to a small extent, while sodium chloride accelerated the conversion.