Studies were made on the occurrence and standing crop of algae from six localities in Muthupet estuary for a period of six months from March to August 1988. Totally 19 afgae belonging to the groups Chlorophyta, Phaeophyta, Rhodophyta and Cyanophyta were recorded. The green algae numbered more than other algae in all the stations. The biomass estimated for Gracilaria verruocsa, Hypnea valentiae and Enleromorpha spp. varied from 905 to 1220 gm/m2, 740 to 980. gm/m2 and 53 to 72 gm/m' respectively