All the physico-chemical parameters such as temperature, LEC, salinity, pH, dissolved oxygen and nutrients like total phosphorus, inorganic phosphate, nitrite and silicate studied in relation to shrimp farming. There are as many as 42 shrimp farms situated on the banks of Vellar estuary. These farms discharge the used water into the estuary, which may influence the biota there. In the present study the physico-chemical feature in relation to shrimp farming were studied in 3 stations of the estuary. When compared with the previous data from Vellar estuary there was no much difference in physico-chemical characteristics due to shrimp farming.