Water, like, air is one of the most important and natural resource and abudantiy available on the earth. River contained 0.004% or 12 X 103 Km3 of fresh water and 0.00008% of total fresh water with 0.031-year turn over period. As a consequence of rapidly expanding industrialization and excessive population growth mostly the river, lakes, streams and other water bodies are being increasingly polluted due to change its quality or composition, directly or indirectly, as a result of man kind activities so that it becomes less suitable for drinking, domestic, fisheries or other purposes for which it would otherwise be quite suitable in its unpolluted state. Polluted water may transmit various type of water borne diseases and many other diseases of epidemic dimensions. The biological information along with physico-chemical information can be of great significance in river quality monitoring. The importance of primary productivity studied in aquatic environment is well realized in view of its value in estimating the productive capacity. Phytopankton constitutes a major faction of primary producers in river ecosystem. Primary productivity of a particular water body gives quantitative information about the amount of energy available to support bioactivity In the system. The community structure and abundant of planktonic algae are dependent on the physico-chemical nature of the river water. The present study has been undertaken on the river Gomati which is consider to be one of the most important tributaries of the river Ganga in U.P. During its flow the river receives diverse pollutants through the waste water discharge from the different ways. The present study was carried out from May 2001 to April 2002.