A process for preparing alkoxytriazolinones of general formula (1):
in which R1 and R2 independently represent an alkyl group, an aryl group, an arylalkyl group or cycloalkyl group. The alkoxytriazolinones are prepared by reacting, in a first stage, water-dissolved iminocarboxylic acid diesters in the presence of a mineral acid or by reacting a mixture of water with a water-miscible polar organic solvent and a carboxylic acid ester, yielding hydrazine carboxylic acid ester; and in a second stage, by further reacting the thus obtained reaction product with an amine, a polar organic solvent or mixtures thereof in the presence of water.