The antibacterial action of a light-cured glass polyalkenoate Vitrebond and an adhesive resin luting agent Panavia Ex was investigated and compared with six previously tested dental cements. The bacterial cultures used were six strains of Streptococcus mutans, six of Streptococcus sanguis and six cultures of carious debris from carious lesions. A modification of the agar diffusion method was used to test the antibacterial action of freshly mixed cements. In addition the cements were allowed to set and their antimicrobial action was tested by incubation for 5 days in sucrose broth inoculated with the test cultures. All the freshly mixed materials had an antibacterial action. A two-way analysis of variance and Tukey-Student range analysis showed that Vitrebond had a significantly greater zone of inhibition than Aquacem, IRM, Dycal, Dycal VLC, Ceramco and GC Elite (P = 0.001). Freshly mixed Panavia Ex exhibited minimal antibacterial action. After 5 days the antibacterial properties of all the cements were reduced.