Public libraries serve as vital centers of public, cultural, and artistic life within local communities. Recognizing their potential as catalysts for change, they play a pivotal role in enhancing the quality of life for citizens in their respective areas of operation. Library materials constitute the most fundamental resource within libraries, thus, the development of library collections and funds is approached systematically, purposefully, and in accordance with professional recommendations. The formulation of a document known as "acquisition guidelines" facilitates the standardization of criteria and values not only in the acquisition policy process but also in the assessment of the existing library fund. Librarians in public libraries are mandated to possess this document, albeit they are not obliged to publicly disclose it. In the theoretical and research segments of this paper, an endeavor is made to address the impact of acquisition guidelines on the operations of Croatian libraries, with a particular emphasis on county central libraries. Research findings indicate a significant percentage of libraries with guidelines, underscoring the necessity for heightened engagement in this domain. Guidelines serve as a form of "identity card" for the library, underscoring the significance of transparency and communication to all stakeholders regarding the library's mission, strategy, and objectives.