AIM: The integration of short physically active breaks into the education system is one of the modern methods of encouraging physical exercise, which aim to have a positive effect on the overall well-being of students. The aim of this research was to determine the impact of 5-minute physically active breaks during classroom lessons on students' educational achievements, students' attitudes towards physical activity and the level of students' physical activity. METHODS: The group random sample of respondents consisted of 229 students, from a total of 12 classes at the Bogoslav Šulek elementary school in Slavonski Brod. During the 16 weeks that the intervention lasted, the students took part in 5-minute physically active breaks 4 times a week in mathematics class. The educational achievements of students were assessed by solving a total of 16 problematic non-numerical tasks and using two standardized tests in the subject of mathematics. Students' attitudes towards physical activity were assessed with the "Attitudes Towards Physical Activity Scale" (APAS) questionnaire at two time points of the examination, as well as the level of physical activity of students, which was assessed using the "Physical Activity Questionnaire for Children" (PAQ-C) questionnaire. Differences between the experimental and control groups in non-numerical mathematical tasks were tested with the Chi-square test, and the differences between these groups in other variables were determined by a two-factor (group x time) analysis of covariance for repeated measurements (RMANCOVA), where the covariates were age and gender. RESULTS: No differences were found in solving non-numerical mathematical tasks at the beginning of the test between the experimental and control groups. However, when individual weeks were analyzed, it was shown that in weeks 6 and 8, students in the control group were significantly more successful, compared to the experimental group, and in week 12, students in the experimental group were significantly more successful, considering the control group. The intervention in the experimental group did not lead to significant time changes in the success of solving standardized tests in the subject of mathematics (arithmetic difference before and after the intervention=-2.14, Z-value=-1.104, p=0.270). The 16-week intervention did not lead to significant differences between the initial and final conditions in both groups in the assessment of attitudes towards physical activity, and there were no positive changes in the experimental group compared to the control group. In the experimental group, only the 'self-efficacy' variable significantly improved in the final, with respect to the initial measurement (t- 11 value=-3.147, p=0.002, ES = 0.40). The results of the PAQ-C questionnaire showed that the experimental group significantly increased the level of physical activity in the domain 'Physical activity for every day last week' (p=0.013), however, the differences between the experimental and control groups in the final measurement were not significant (t-value=-1.889, p=0.060). Also, there were no significant differences in the overall level of physical activity between the experimental and control groups in the final measurement. CONCLUSION: Short physically active breaks in the classroom during the lesson have an insignificant effect on the success of solving problematic non-numerical tasks and standardized tests in the subject of mathematics in the experimental group. It can also be expected that by regularly participating in active breaks, students will form a positive attitude towards physical activity and achieve a higher level of physical activity. The research contributed to a better understanding and recognizing the need to integrate the movement into the educational system, because based on this and future knowledge, it is possible in the school system to plan and program active breaks as part of the school hour, in order to ultimately have a positive impact on educational achievements and positive life habits in childhood.