One of the key competencies for a children’s librarian is to know and evaluate literature for children ˗ books, periodicals, audiovisual materials, websites and other electronic sources, etc. In this respect, children’s librarians can add the most recent and relevant materials to the library collections, meeting both the developmental characteristics of children and needs or interests of each individual. The level of competence in this area is primarily reflected in the quality of library collections, and the impact on library acquisition policy. In addition, it is directly linked with recommending quality literature for children service and other information and reference services. Furthermore, being familiar with the literature for children as well as knowing how to evaluate it professionally has a large impact on the design of various library programs such as the promotion of reading and consulting with parents. Construction of the respective collections is considered to be the basis for the development of most other services. The question is whether it is possible to build and maintain the quality of library collections, and to appropriately design and develop other programs and services if a librarian is not familiar with the published literature. This paper will bring the results of the research aimed to explore the extent to which children’s librarians of the county libraries in Croatia are familiar with the picture books for children and books for younger children. Additionally, it will discuss possible reasons for underdeveloped competencies in this area, and suggest some solutions for the existing problems.