Objectives: This investigation was carried out to study the fluoride release property of three high viscous glass-ionomer restorative materials at six time intervals which left to set without ultrasound application or subjected either to 20s or 40s of ultrasound application (UA) during setting.Materials and Methods: A total of 90 specimens were prepared from three different glass-ionomer restorative materials (GIRMs) (30 specimens each): Ketac-Molar Aplicap, Fuji IX GP Fast and ChemFil Rock. Specimens of each group were further subdivided into three subgroups, 10 specimens each, according to the time of ultrasound application during setting. One acting as a control subgroup (not subjected to ultrasound application) and the other two were subjected to either 20s or 40s of ultrasound application representing U2 and U3 subgroups, respectively. All specimens were planned to be tested for fluoride release property and the same specimen is re-evaluated at the proposed storage periods. T1- T6 represents different time intervals at which specimens were measured corresponding to 1, 2, 3, 7, 14 and 28 days, respectively.Results: The effect of ultrasound application during setting was statistically insignificant in respect of fluoride release property for all the tested GIRMs at different time intervals. Furthermore, Fuji IX GP Fast GIRM showed the highest fluoride ion level followed by Ketac-Molar Aplicap and the least release was recorded by ChemFil-Rock GIRMs during the test periods. Concerning the effect of time, all the glass-ionomer restorative materials recorded a high initial burst of fluoride ions during the 1st day, then the release was decreased linearly until became in a steady state, where the fluoride release values reported the least amount at the 28th day. Conclusion: Ultrasound application during setting of glass-ionomer restorative materials may have no positive effect on the fluoride release level; however this release is material and time dependent.