Abstract: Andrographis paniculata Burm.F(Acanthaceae) is a potent medicinal plant in the Indian systems of medicine. Traditionally the leaves are used as/in influenza, bronchitis, gonorrohea, cholera, fertility and antibacterial, anticancer, antidiabetic, anti-inflammatory and anti snake venom etc. In the present study the aqueous and methanol extracts of the leaves, stem, root and whole plant of Andrographis paniculata were studied for their antibacterial activity by Agar-well diffusion method against different gram-positive (Staphylococcus aureus and Bacillus subtilis) and gram- negative (Escherichia coli, Klebsiella pneumoniae and Proteus vulgaris) bacteria. It was observed that, methanol extracts of whole plant and leaves showed the significant antibacterial activity against Gram-positive bacteria. No bacterial activity was recorded with aqueous extracts of stem and root. Key words:Andrographis paniculata, Agar-well diffusion method, Methanol extract, Antibacterial activity