The most sensitive user group in libraries are young adults – people aged 12 to 20. Materials selected for young adults has to address their intelectual, emotional and social needs to help them successfuly transition from childhood to adulthood. Collection development consists of selection, acquisition, weeding and assesment. In order to develop quality collections, librarians create a collection development policy based on the research of their users' needs. The policy is also a base for the selection – a process of choosing the proper materials. This thesis, based on literature regarding working with young adults and collection development, researches basic assumptions and conditions for developing quality collections for young adults, as well as the issues regarding this specific user group. Special attention was given to the selection and criteria librarians use when selecting the materials for young adults. In order to question theoretic discoveries, the processes of developing services and collections for young adults in Public library Zadar were researched. The librarians working in their Childrens' and young adults' department were interviewed to determine the age group their services for young adults are intended for, which criteria and sources they use when selecting materials for young adults and whether they develop those services and collections in partnership with young adults. Also, the Guidelines for acquisition of materials in Public library Zadar were analyzed considering the criteria for selecting materials for young adults discovered in literature.