Apart from their release of fluorine ions, GICs can potentially be used as templates for the release of other active antimicrobial ingredients. The aim of this study was to investigate the possibility of incorporating an antimicrobial compound into a glass-ionomer cement. For the realization of the aim set we used the commercially available ChemFlex glass-ionomer cement, a material widely used in restorative dentistry. Three groups of the commercial ChemFlex glass-ionomer were prepared, with no antimicrobial compound added, of 5 samples each - to serve as a control group; and another three groups of the same cement of 5 specimens each were also prepared, but each with a different concentration of benzalkonium chloride added to it - 1%, 2% and 3%, respectively - a total of 15 samples. The concentrations of released ions - fluoride and chloride - were measured at predetermined time instants. In order to determine the amount of ions (Cl(-) and F(-)) released into the medium (deionized water) in which the samples had been placed, we conducted measurements with ion-selective electrodes for chloride and fluoride at different time instants. We carried out an analysis of the release of chloride in order to see whether and in what concentrations such release of chlorine, a constituent of benzalkonium chloride, occurs, and thus to conclude about the possibility of the antimicrobial effect of the glass-ionomer cement. The common feature of all three percentages of benzalkonium chloride was that there were differences between the concentrations of chloride released by the samples with and without the antimicrobial compound added.