The present study deals with the investigation of the In vitro antibacterial activity of the plant extract of Anisomeles Malabarica linn leaves. The preliminary phytochemical analysis of the solvents extracts in water, petroleum ether, ethyl acetate and methanol revealed the presence of alkaloids, flavonoids, tannins, terpenoids, carbohydrates, phytosterol and coumarin. The TLC technique was used to identify and separation of possible compounds present in the methanol extract. The FT-IR spectral data shows the possible functional groups of chemical compounds present in the methanol extract of A.Malabarica. The methanol extract only used for the biological activity. The crude methanol extract of the leaves was used to evaluate the antibacterial activity by Disc Diffusion Method. The present study was carried out to evaluate In vitro antibacterial activity of the leaves methanol extract of A.Malabarica against Escherichia coli, Bacillus subtilis, Staphylococcus aureus, Pseudomonas Auregenosa, and Klebsiella pneumonia. It was found that the methanol extract exhibited a maximum antibacterial activity at 100 μl/ml and produced 21mm zone of inhibition against both E.coli and P. Auregenosa. The results provide justification for the use of A. Malabarica to treat various infectious diseases.