Aim: The aim of the present in vitro study was to evaluate the antibacterial activity of S-PRG resin composite versus conventional glass ionomer cement. Materials and Methods: A total number of Forty cylindrical disc formed specimens for antibacterial activity test were made in a standardized sterile teflon mold with an internal diameter of 6mm and a thickness of 2 mm were assigned into two equal groups: S-PRG resin composite and conventional glass ionomer cement. For S-PRG resin composite the sterile teflon mold were put on the highest point of a sterile glass slide (1.2mm thickness) and a celluloid strip (0.05mmthickness), the restorative material samples were packed into the mold using gold plated composite applicator, the second celluloid strip was used to overlay the top side of the mold to inhibit formation of air inhibited surface layer. Additional glass slide and the weight 500gm were used to give a consistent, good packing of the specimens and to extrude the excess material. Employed weight and glass slide were eliminated, light cured for 10 seconds (wave length range 440-490 nm)from the top, bottom and sides. The tip of the light curing unit was kept focused in direct contact with the celluloid strips on the top surface of the mold perpendicular to it.