A process for continuous production of C2-C4-monoalkanolamines by reaction of a corresponding C2-C4-alkylene oxide with a molar excess of ammonia (NH3), wherein aqueous ammonia is employed, in the liquid phase and in the presence of an acidic cation exchanger as catalyst which contains a crosslinked copolymer comprising acidic functional groups as the carrier matrix, wherein the cation exchanger has a total exchange capacity of not less than 1.8 eq/L.