The Gram-positive bacterium Enterococcus faecalis is an etiological agent of endodontic infections in oral biofilms. In the present study, we analyzed the effect of N-acyl homoserine lactones (AHLs) quorum sensing signal molecules on E. faecalis biofilm formation ability. Our results provide important effects of N-Hexanoyl-L-homoserine lactone (C6-HSL) and N-octanoyl-L-homoserine lactone (C8-HSL) molecules on E. faecalis biofilm formation. These AHLs molecules promoted the biofilm formation of E. faecalis.