Seaweeds constitute one of the commercially important marine living renewable resources. They are the only source for the production of phytochemicals such as agar, agarose, carrageenan and algin which are widely used in various industries as gelling, stabilising and thickening agents. Seaweeds are good sources of food and medicine. Food products like jelly, jam, pickle etc. can be prepared from seaweeds. Many bioactive compounds can be extracted from seaweeds. Seaweed meal and seaweed liquid fertilizer are also' manufacture.d from marine algae. The methods for manufacturing different phyto-chemicals and products from seaweeds are given in this paper.