Physical activity is defined as any movement that is realized by the ratio of the skeletal and muscular organic system. In addition to the general definition, physical activity can be seen in a series of everyday activities, including kinesiology activities in terms of sports. The positive impact of physical activity can be applied to the entire organism of each individual, from a series of benefits in the areas of physical condition to psychological and cognitive aspects. The cognitive mechanism of a person's functioning is of considerable importance in perceiving, processing, integrating and storing different information of the greatest exposure, which occurs during the period of attendance at the compulsory educational program. Pupils and their knowledge are evaluated at the end of the learning cycle, which results in receiving a certain grade. The obtained grade actually represents the academic achievement realized by the student after the learning process. Namely, the aim of this research is to establish whether playing sports is related to the academic success of students in the fourth grade of primary school education. Physical activity of students refers to playing sports, while school success refers to their final grades in the subjects of the previous class. Subjects from the educational area were taken into account because of determination of the interdependence of physical activity and cognitive processes of knowing information in the context of the subjects of the educational area which refers to Croatian language, mathematics and science. According to the conducted research, the collected data and results were presented in tabular and graphic form. However, no statistically significant difference was found in the school success of students who practice sports and those who do not practice it in their free time. Additional research and studies would greatly contribute to the multidisciplinary field of the profession, and thus provide an answer to certain questions that have not yet been fully concluded regarding the interdependence of physical activity and school achievement.