Process for making a chelating agent according to the general formula (I), R1—CH(COOX1)—N(CH2COOX1)2 wherein R1 is selected from hydrogen, C1-C4-alkyl, phenyl, benzyl, CH2OH, and CH2CH2COOX1, X1 is (MχH1−χ), M being selected from alkali metal, x is in the range of from 0.6 to 1, said process comprising the following steps: (a) providing a solid, a slurry or a solution of a compound according to general formula (II a) R1—CH(COOX2)—N(CH2CN)2 wherein X2 is (MyH1−y), M being selected from alkali metal, y is in the range of from zero to 1, (b) contacting said solid or slurry or solution with an aqueous solution of alkali metal hydroxide, wherein the molar ratio of alkali metal ions to nitrile groups is in the range of from 0.6:1 to 0.95:1, (c) reacting said compound according to general formula (II a) with said alkali metal hydroxide.