The Veli Lake is the smallest among the backwaters of Kerala. It is situated 8 km north west of Trivandrum City at 8° 28′ N latitude and 76° 57′ E longitude. The system widens from the bar mouth to the eastern part and is 2 km long and 0.3 km broad. It is shallow with a mean depth of 2-3m. The partially treated sewage and the completely untreated industrial effluents are the main sources that brought undesirable changes in the lake. For the present study three stations were fixed in the lake to test the physicochemical features (April 2000-March 2001).The results show that monsoon represents less polluted zones. The minimum undesirable effects are noticed in the less polluted zones. © Enviromedia Printed in India. All rights reserved. © 2008 Elsevier B.V., All rights reserved.