In this paper, it is claimed that authors adjust their use of phraseology in children’s books to the still limited phraseological competence of children. Authors may apply procedures such as phraseme accumulation, phraseme paraphrasing, or phraseme modification in order to enhance the comprehensibility of phrasemes for children. With increasing phraseological competence of adolescents, the use of phraseology in books for adolescents changes. Three hypotheses are set up: (H1) The phraseme types used in children’s books are semantically and pragmatically rather ›easy‹ compared to those in adolescent’s books; (H2) the number of phrasemes which are accompanied by procedures of enhancing comprehensibility is higher in children’s books than in adolescent’s books; (H3) the type of enhancement procedures used in children’s books is different from the type of enhancement procedures used in adolescent’s books. The hypotheses are quantitatively examined in a comparative case study on Otfried Preusler’s Die kleine Hexe and Krabat.