Antibacterial activity of brown seaweeds viz, Sargassum wightii, S.oligocystum, S.vulgare, Turbinaria ornata, Padina tetrastromatica and Stoechospermum marginatum were tested against Gram positive (Staphylococcus aureus, Micrococcus luteus, Bacillus subtilis) and Gram negative (Aeromonas hydrophila, Pseudomonas fluorescens) bacterial pathogens. The extracts indicated a stronger activity against Gram positive bacteria than Gram negative bacteria. Methanolic extracts displayed significantly higher antibacterial activity against all the bacterial pathogens followed by acetone extracts. Methanolic extracts of T.ornata and P. tetrastromatica exhibited the maximum antibacterial activitywith inhibition zone measuring of 13±0.2 mm and 12.1± 0.4 mm respectively against the Gram positive bacteria viz., B.subtilis and M.luteus. While the control or the water extracts of fucoidan revealeda weak or no activity against the microorganisms tested