The reaction of 2,4-dinitrotoluene with an ozone-oxygen mixture in glacial acetic acid in the presence of transition metal salts was studied. The ozonolysis of the aromatic ring during the process in the presence of cobalt(II) or manganese(II) acetate was prevented to a considerable degree, and selective oxidation at the methyl group of 2,4-dinitrotoluene became prevalent, producing 2,4-dinitrobenzoic acid with a yield of 87.6 or 73.1%, respectively. A decrease in the yield of 2,4-dinitrobenzoic acid with an increase in the temperature of ozonolysis in the presence of manganese(II) acetate was found to be due to partial transition of the oxidized manganese form Mn4+ into the insoluble form MnO2.