Purpose: The aim of the study was to measure and compare the release of fluoride ions from three bioactive restorative materials used for restorations in primary dentition - conventional GIC Fuji IX GP Extra, compomer Dyract and giomer Beautifil II. Materials and methods: 20 samples with a diameter of 6 mm and a thickness of 2 mm were made from the tested materials. At the beginning of the test, all samples were immersed in 5 ml of deionized water and placed in an incubator for 24 hours at 37°C ± 0.5°C. After 24 hours, the concentration of fluoride ions in the medium was measured with an ion-selective electrode for fluorides connected to an ion meter. During this time, the removed cylindrical samples were washed with fresh deionized water, dried, and transferred to new vials with 5 ml of fresh deionized water. The described procedure was repeated every day for a week and then on the 14th, 21st and 28th days. Results: GIC outperformed compomer and giomer in terms of fluoride ions release for all time intervals with a statistically significant difference. The difference between compomer and giomer was not reliable, but compomer demonstrated higher values for all time intervals. Conclusion: All studied materials released fluoride ions during the entire experimental period, with the highest concentrations being recorded on the first day of the study. GIC outperformed compomer and giomer many times in terms of fluoride release for all time intervals.