The objective of the present study is to describe the pharmacognostical and phytochemical investigation of selected marine seaweeds of Rhodophyceae from the coastal areas of Manapad, Tamil Nadu state. The pharmacognostic studieswere carried out in terms ofmorphology, anatomy, ash analysis and fluorescence analysis. Preliminary phytochemical screening of secondary metabolites was carried out by the method described by Brindha et al. The results of ash analysis showed the presence of more amount of total ash followed by sulphated ash in all the seaweeds compared to water soluble and acid insoluble ashes. In fluorescence analysis, most of the treatment show the characteristics of different shades of green under visible and UV light Qualitative analysis of selected seaweeds revealed the presence of steroids, triterpenoids, alkaloids, tannins, phenols, saponins, flavonoids, catechine, anthroquinone etc. in methanol and aqueous extracts. TLC studies showed different Rf values with high resolution and reproducible peaks. These studies will help themanufacturers for identification and selection of rawmaterials for drug production.