The antibacterial activity of different extracts of M.oleifera root bark was investigated against Staphylococcus aureus, Escherichia coli, Sa lmonella gallinarum and Pseudomonas aeruginosa in vitro . Both the gram-positive and gr am-negative organisms showed variable sensitivity to different extracts of M.oleifera roo t bark in organic solvents like methanol, acetone, ethyl acetate and chloroform and in inorga nic solvent, water. In general, ethyl acetate and acetone extracts showed maximum antibac terial activity. The aqueous extract had minimum antibacterial activity against the test organisms.