Aim: An in vitro study to evaluate and compare the antibacterial efficacy of giomer and compomer against Streptococcus mutans (S. mutans) and Lactobacillus acidophilus (L. acidophilus). Material and methods: Antibacterial activity of giomer (Beautifil flow plus, Shofu Inc., Kyoto, Japan) and compomer (Dyract XP, Dentsply, Germany) was assessed using the agar diffusion test, in triplicate. Test specimens for both the dental materials were prepared using a custom made teflon ring mold with a diameter of 6.5 mm and thickness of 2 mm and inserted into the punched wells (6.5 mm x 2 mm) in the BHI agar, 0.2% chlorhexidine digluconate placed in other well acted as a control. The agar plates were incubated at 37o C for 24 hours, later size of the inhibition zones was measured (in mm) by digital vernier caliper at three different points at 24 hours, 48 hours and 7 days interval. Results were tabulated and subjected to statistical analysis. Results: Nearly 0.2% chlorhexidine, the control group showed an inhibition zone, whereas the restorative materials did not show the inhibition zone as well the antibacterial efficacy against S. mutans and L. acidophilus. Conclusion: None of the hybrid esthetic restorative material tested in this study possesses antibacterial properties.