Methanolic extracts of 17 commonly found seaweeds in the west coast of India were screened for the presence of antimicrobial activity against Bacillus subtilis, Escherichia coli, Pseudomonas sp., Streptococcus pyrogenes, Staphylococcus aureus, Proteus vulgaris, Klebsiella pneumoneae, Serrratia marganii and Candida albicans. The results of this study indicated that the extracts of Padina tetrastomatica and Jania rubens, brown and red alga respectively, were promising. Further purification of the active extracts followed by bioassay indicated that fraction of Ethyl Acetate (EtOAc) was more active as compared to other fractions. Phytochemical investigation revealed the presence of phenols, tannins, saponinis, cardiac glycosides, terpenoides, alkaloids, anthraquinones and flavonoides.