Abstract: A continuous process for the preparation of monoethanolamine, diethanolamine and triethanolamine by reacting ammonia and ethylene oxide in liquid phase in the presence of water as catalyst in a pressure column is proposed, where, as a result of the heat of the reaction, some of the ammonia evaporates, condenses at the head of the column and is again charged to the column, the reaction mixture at the bottom end of the pressure column is drawn off and then separated, the pressure column is constructed as a reactive distillation column (I) with evaporator at the bottom (S) and where, by means of inputting energy via the evaporator at the bottom (S), the weight ratio of monoethanolamine to diethanolamine to triethanolamine is controlled and, via the ratio of ammonia to ethylene oxide in the feed to the reactive distillation column (I), the ammonia proportion in the bottom product from the reactive distillation column (I) is controlled.