10.22376/ijpbs.2019.10.1.p1-12 Volume 4 Issue 1 2013 (January - March) Biofilms have been proved to have useful effects on food chains, sewage treatment plants, to eliminate petroleum oil on oceans. They have been found to cause a wide variety of microbial infections in the body, such as urinary tract infections, catheter infection, middle-ear infections, formation of dental plaque, gingivitis, coating contact lenses. In the present study, the high yielding biofilm strains have been isolated from the soil. Microtitre plate assay was used to confirm the biofilm producing ability of these bacteria. Two high yielding isolates were identified and characterized. Both the isolates were named as sample 17 and sample 19. The isolates were characterized by biochemical and molecular techniques. The antibiofilm activities of various chemicals and plant extracts have been tested. Ethanol, formaldehyde, hydrogen peroxide showed considerable effect, iodine showed negligible effect on the biofilm formation. The extracts from lessThan i greaterThan Prosopis juliflora, lessThan /i greaterThan lessThan i greaterThan Nerium oleander, Eucalyptus globulus lessThan /i greaterThan and lessThan i greaterThan Catharanthus roseus lessThan /i greaterThan showed significant reduction on biofilm formation. lessThan i greaterThan Calotropis gigantea, Ocimum sanctum lessThan /i greaterThan and lessThan i greaterThan Ricinus communis lessThan /i greaterThan did not show any effect on biofilm formation. KOKKILIGADDA SUJANA, KARLAPUDI P. ABRAHAM, INDIRA MIKKILI AND KODALI V PRABHAKAR Biofilm, Plant extracts, chemical agents, Exopolysaccharide, Microtitre plate assay, Tube method. 702-712