The aim of the present study was to evaluate the anti bacterial activity of Acacia catechu on selected oral microbes. Acacia catechu [AC] is a moderate thorny deciduous tree growing in tropical countries. Antibacterial activity of ethanolic and aqueous extract of heart wood of AC is screened against Streptococcus mutans, Streptococcus salivarius, Lactobacillus acidophilus and Enterococcus faecalis using disc diffusion technique. The Minimum inhibitory concentration [MIC] and Minimum bactericidal concentration [MBC] of the extracts were also determined. The results of this study showed that both the extracts at different concentrations exhibited anti bacterial activity against the bacterial species tested. The ethanolic extract showed higher degree of activity than aqueous extract when compared with the standards.