A textbook is a basic and compulsory teaching aid, written on the basis of a prescribed curriculum. The accompanying materials in the textbook are certainly illustrations that, in addition to serving the basic text, can also have a significant effect on the student. The aim of this research was to examine the representation of illustrations in textbooks used from the first to the sixth grade of primary school. An analysis was performed of forty elementary school textbooks approved for use by the Ministry of Education of the Republic of Srpska, with the basic unit of analysis being the illustration in the textbook. The obtained research findings show that in both the first and the second triad, illustrations without humorous elements are more represented, although the number of humorous illustrations is at an enviable level, illustrations directly related to the content of the text predominate, drawings in both triads are most represented, and the largest number of illustrations have an intellectual value. A comparative analysis of the illustrations in the first and second triads shows that the differences can be read in terms of the categories of representation of illustrations on the pages and the functions of facilitating the memory or comprehension of the text. The obtained results are encouraging because they confirm the success of the assumptions for effective learning in accordance with age characteristics certain illustration requirements have been met, and the study can provide useful information to textbook developers, teachers, parents, and illustrators, given that illustrations are a structural element of a textbook to which students should be referred. The results can also be useful for the shaping and deeper operationalization of art and graphic requirements in the textbook and can influence the improvement of textbook quality standards.