This study was undertaken to examine whether a relationship exists between the composition of metal-containing glass-ionomer cements and ion release from these materials. Conflicting data on silver release from this type of material has been reported and it was felt that further investigation was desirable in view of the increasing use of these materials. In this study, the release of ions, particularly of silver and fluoride, into deionized water and artificial saliva was measured for up to one year. Low levels of silver and copper ions were found in both media. The amounts released from alloy-containing materials were dependent on the amount of alloy present; lesser amounts were leached from cermets. Fluoride ion release was less material-dependent but still lowest for cermets. The use of artificial saliva reduced ion release as did increasing the maturation time prior to immersion in either liquid.