The present paper deals with the seasonal abundance and distribution of micro algae in the estuarine habitats of the Gosthani River near Bhimili, Andhra Pradesh, India. Water samples were collected for a period of one year from January 2023 to December 2023. A total of 44 species belongs to four major groups such as Chlorophyceae (12), Cyanophyceae (7), Euglenophyceae (5) and Bacillariophyceae (20) were reported from the estuarine regions of Gosthani River. The density of phytoplankton populations in Gosthani estuary varied seasonally with maximum number of cells per liter (5186) was observed in the month of March and minimum number of cells (789) was recorded in the month of August.