Because of the relatively frequent occurrence of recurrent caries after a restorative treatment, and because of the huge number of cariogenic microorganisms present in the oral cavity, which present a potential risk factor regarding the development of new carious lesions, attention has increasingly been directed towards the therapeutic antimicrobial effects of restorative materials. The glass ionomer cements distinguish themselves as the most acceptable restorative materials possessing the positive characteristics of fluorine in the processes of remineralisation and antimicrobial action. In addition to the release of fluoride ions, GICs can potentially be used as templates for the release of other active antimicrobial components. The addition of antimicrobial compounds in the glass ionomer cements and analysis of their physical characteristics are very important especially for use in the posterior region of milk teeth. The aim of this study was to analyse the physical characteristics of ChemFlex and Fuji IX, conventional glass ionomer cements incorporated with the antimicrobial components Cetylpyridinium Chloride and Benzalkonium Chloride, through measurements of their setting times, and determination of their compressive strengths. Five samples of each glass ionomer with no antimicrobial compounds added were prepared--to serve as a control group; and collections of five samples of each cement with different concentrations of Cetylpyridinium Chloride and Benzalkonium Chloride--1%, 2% and 3%--added to them were also prepared--a total of 60 samples. The results of the analysis point out that it is possible to incorporate these antimicrobial agents in conventional GICs, and this is especially true when the added amount of the antimicrobial agents is 1%.