A process for the preparation of a .omega.-(O-substituted urethano)alkylcarboxylate, wherein a lactam having from 4 to 9 ring members, which can have alkyl, alkenyl, cycloalkyl, or aralkyl groups containing up to 12 carbon atoms as substituents, is reacted with a carbonic diester of an alkanol, alkenol, cycloalkanol, or aralkanol containing up to 16 carbon atoms, at a temperature of from 25.degree. to 300.degree. C. in the presence of a catalytically effective amount of a base.