Hexane, chloroform, methanol, chloroform: methanol (2:1 v/v) and petroleum ether extracts of Turbinaria conoides from the coast of Mandapam were tested in vitro for their antibacterial activities against Escherichia coli, Salmonella typhi, Staphylococcus aureus, Pseudomonas aeruginosa and Proteus mirabilis with the disc diffusion method. Petroleum ether was the best solution for extracting the effective antibacterial materials from the Turbinaria conoides used in this experimental and compared with standard drug, Amoxycillin. The present findings show the importance of Turbinaria conoides in producing new compounds having antibacterial activity.