Preparation process for 4-substituted dinitroanilines of formula ##STR1## in which R.sub.1 is chosen from the group containing the tert-butyl, sulphonamido, trifluoromethyl, methyl-sulphonyl and isopropyl radicals,R.sub.2 and R.sub.3, which are identical to or different from one another, represent a hydrogen atom, a linear or branched alkyl, cycloalkyl, haloalkyl or alkenyl radical containing less than 6 carbon atoms, characterized in that that it comprises successively:a dinitration stage of the 4-substituted phenol corresponding to the sought 4-substituted dinitro-aniline, this dinitration stage being carried out in a reaction medium containing a slight excess of nitrating agent, a sufficient quantity of protons and a catalyst chosen from the group containing the soluble salts of the transition metals of columns IV to XII of the Periodic Table, preferably the soluble salts of Fe.sub.III, Fe.sub.II, Zn.sub.II and Cu.sub.II ions,an O-alkylation stage of the dinitrated 4-substituted phenol obtained in the preceding stage, by means of an alkylating agent, andan amination stage of the 4-substituted dinitrated phenoxy-ether obtained in the preceding stage by using a primary or secondary amine.