There exist an estimated 3 million to 500 million different species in the marine biosphere representing approximately a half of total global biodiversity and 7000 species of which are marine algae. Algae are one of the oldest living organisms on the earth. They have been found as fossils from the Precambrian period and are estimated to be 1 to 3 million years old. Marine macro algae or seaweeds are distributed widely in all oceans of the world. These plants present a number of challenges to chemists, biochemists and ecologists alike, obviously for the reason that these organisms have survived the global changes that have been happening in the intervening millions of years of evolution. It would be reasonable to assume that this survival mechanism was directly related to the metabolites which imparted a unique strength of adaptability on these plants. What else could be more attractive a renewable bioresource than seaweeds to work on? Seaweeds have been reported to be bioactive of different kinds e.g. neurotoxic, hypotensive, cytotoxic, AIDS antiviral, antithrombic, immunomodulatory and anticancer. There is a possibility that these can be developed into drug or drug intermediates. Seaweed polysaccharides e.g. agar, agarose, carrageenans and alginate have been well known to be used as gelling and thickening agents in food and other industrial uses. Recent applications include its use as biomaterials which can be used in pharmaceutical and health care industries. These being renewable resource-based materials hold promise for potentially new and sustainable applications. In this article these aspects will be described with a focus on Indian scenario. India has been identified as one of the 12 mega-diversity countries. The work that has been done in the area of seaweeds research including large scale cultivation and value addition, pushing seaweeds up the value chain particularly the species of Indian waters, which were little known for their utility, will be described.