Coastal environment is a highly productive and economically important ecosystem. The oceans cover 71% of the earth surface and provide maximum benefit to human beings. The environmental conditions of coastal waters are largely governed by the seasonal and tidal cycles. Marine processes and food chains start with phytoplankton, which are chlorophyll-containing organisms. Nutrient enhancement in the seawater due to the discharge of agricultural, industrial, and urban wastes threatens the Sea environment. The different sampling stations of the coastal waters for the collection of water samples. The sampling stations were fixed based on the distance, accessibility and pollution load. The samples were collected and analysed for chlorophyll 'a'. During the month of December-2009, January-2010 and February-2010 in the following sampling stations. Ennore- Station-I, Harbour - Station-II, Coovum - Station-III, Marina - Station IV, Adyar - V and Thiruvanmiyur - VI. In the month of December station I and station IV showed higher chlorophyll ‘a’ levels when compared to other stations, control station showed highest level in January and February similar results were obtained, when compared to the other stations, but there was increased chlorophyll a level in all stations compared to December.