A process for preparing a salt-free aqueous hydroxylamine solution by reacting an aqueous solution of a hydroxylammonium salt with a base to give a mixture and separating from said mixture by distillation a salt-free aqueous hydroxylamine solution, involving using as a base an aqueous solution of a mixture of NaOH and KOH in a molar ratio Na.sup.+:K.sup.+ in the range from 70:30 to 95:5 and with a total concentration of Na.sup.+ and K.sup.+ in the range from 0.1 to 10 m/m % based on the total amount of the mixture.