Abstract: The sediment is the ultimate sink of contaminants in the aquatic systems. The study was conducted to assess the sediment physico-chemical parameters of Sewri mudflats. Sediment samples were collected for a periods of 13 months from November 2008 to November 2009 at low, mid and high tides area from 9 different stations near Sewri jetty. Samples were analysed for temperature, pH, moisture content, sediment texture (sand, silt and clay), total phosphorus and organic carbon of sediment. Pearson correlation coefficient was used to analyse the data. Sediment average values of temperature, pH, moisture content, sand, silt, clay, total phosphorus and organic carbon were respectively 26.3 0C, 7.4, 76.6 %, 5.6 %, 48.5 %, 45.9 %, 3288 µg g-1 and 3.1 %.The Moisture content was slightly higher attributed to silty clay to clayey silt nature of sediment. Total phosphorus and organic carbon showed marginally higher values which can be attributed to organic load. Throughout the study benthic phytoplankton and 3 groups of macrobenthose were observed.