The antibacterial activity of seven commercially available dental cements (Eugespad, Dentical, Dycal, Expaliner, PR. Scell, PR. Base Cement, PR. Lining Cement) against 1) bacterial species implicated in carious lesions or in dental plaque (Actinomyces israelii ATCC 10048, Actinomyces viscosus ATCC 19246, Streptococcus mutans ATCC 25175, Streptococcus sanguis ATCC 10557) and 2) bacterial samples of stimulated saliva was studied, in vitro, using a modification of the method of McComb and Ericson (1987). Dycal and Expaliner did not affect bacteria whereas the other dental cements displayed some antibacterial properties. Eugespad was the most active followed by PR. Base Cement + PR. Scell + Dentical and by PR. Lining Cement. Associated with mechanical and biocompatibility properties, these differences could be taken into account when choosing a dental cement for clinical use.