Chilika Lake is the Asia largest lake and largest tropical lagoon in the world which contains wide range of sub ecosystems such as mudflats, freshwater marshes, sand dunes and a shallow brackish lake. It is the first Indian wetland which got international importance under the Ramasar convention due to its rich biodiversity with over 400 different types of brackish and fresh water species, but the lake is under constant pressure of natural and anthropogenic activities which can lead to ecological transformations. This study demonstrates the spatiotemporal changes of Chilika Lake in the period of 1988-2017 using multi-temporal Landsat 5-TM and Landsat 8-OLI images. The satellite derived Normalized Difference Water Index (NDWI) was used to investigate the dynamics of surface water, extracted from Landsat data. Minimum (Min.), Maximum (Max.) and Mean pixel value extraction method from each NDWI image was applied and generated annual composites for the above years, to identify the lake area. Results obtained from Min., Max., and Mean method, indicates the increasing and decreasing trend in lake surface area in the period of 1988-2017. Results from Min. and Mean methods shows the Increase in lake area from 282 to 440 km² and 665 to 768 km² respectively; while results obtained from Max., shows slight decrease in lake area from 959 to 957 km² in the period 1988-2017.