The reading culture, which is generally created and strengthened through works of children's literature, has important functions in the mental (cognitive), spiritual, social, moral, linguistic and aesthetic development of children. If children encounter high quality books that are suitable for the principle of appropriateness for the child from their infancy period will put their reading culture on a solid and healthy foundation that will last throughout their lives. Public and children's libraries are social institutions that bring children together with various types of numerous children's books. However, they need to have a collection of children's books which are in high quality and which appeal to children in order to fulfill their significant role in promoting reading culture. Objective: This study aims to examine the illustrated preschool (early childhood) books in the collection of Eskisehir Provincial Public Library in terms of their physical (external) and content (internal) characteristics and the principle of relevance to the child, and to reveal the impacts of this on borrowing. Method: Therefore, the scope of this study covers the illustrated printed books in Turkish for children aged 0-7 in the collection of Eskisehir Provincial Public Library which were published between 2015-2019. 130 books were used as a sample and population of the research is comprised of 2,197 books. In the research carried out with descriptive method, physical and content characteristics of sampled illustrated children's books and data related to the principle of relevance to the child were analyzed through "Illustrated Children's Books Evaluation Form" created by the researchers and evaluated by associating them with their borrowing status. Findings: According to the findings obtained in the study, 60,8% of children's picture books in Eskisehir Provincial Public Library are borrowed 1-3 times a year on average; while 56,2% of thick paperback books are borrowed 7 times or more per year on average, this rate is 5,3% for thin paperback books; 81,9% of original children's books and 96,6% of translated children's books were borrowed; while 96,6% of children's picture books with visually appealing covers are borrowed, this rate drops to 81,7% for books whose covers are not visually appealing; 94,7% of the books that are suitable for the child's interests and needs are borrowed, the rate of borrowing decreases to 66,7% for the books that are not suitable for the development of the child and to 81,2% for those that are partially suitable. It has been understood that 98,2% of the children's picture books that will arouse the desire to read in the child, 89,5% of the partially in this quality and 72,3% of the unqualified children's books are borrowed at least once a year. Implications: The results of the study shows that illustrated children books in the Eskisehir IHK collection are borrowed 1-3 times in average per year; the publication information in these books has not effect on the annual borrowing frequency but the characteristics of being original or translated affects the frequency of borrowing; there is no statistically significant correlation between the size of the books, availability of information relevant to the target age group on the books and the annual borrowing frequency; the attractiveness of the cover images, the fact that the cover images reflect the content (theme), the relevance of the pictures to the children to create a story, and the suitability of the picture and text ratio affect the borrowing.