BACKGROUND This study measured the amount of fluoride released from three light-activated glass polyalkenoate (ionomer) cements, a conventional glass polyalkenoate, a compomer and a fluoridated composite over a period of 12 months. METHODS Five discs (7 x 2 mm) of each material were sequentially immersed in 4 mL portions of deionized water at 37 degrees C and before each measurement, the test specimen was rinsed with 1 mL of deionised water. An Orion Model 901 microprocessor digital Ionalyzer was used for the measurements and the data obtained were converted into microgram/cm2. The amount of fluoride released was measured 86 times during the 12-month test period. RESULTS It was found that the pattern of fluoride release from the light-activated glass polyalkenoates was similar to that of the conventional glass polyalkenoate. The light-activated glass polyalkenoates, however, released significantly more fluoride than the conventional material. The composite and the compomer released significantly less fluoride than any glass polyalkenoate tested and the difference between the composite and the compomer was not significant. CONCLUSIONS It was concluded that the light-activated glass polyalkenoates tested released more fluoride than a conventional glass polyalkenoate, a compomer or a composite, and that with regard to fluoride release the compomer behaved more or less like the composite.