It is a known fact that GIS is an extra-ordinary powerful tool that has a wide spread application in almost all the fields, starting from urban planning to crime analysis. In this array, GIS can be well used in disease survelliance mapping. GIS contains two closely integrated databases:One spatial(locational) and the other non-spatial(statistical).A blend of these two databases turns GIS into a powerful analytical tool.GIS provides ideal platform for analyzing diease-specific information with respect to population settlements,surrounding social environment and the climatic conditions. Leptospirosis is an infectious diease,more commonly,transmitted to the humans by allowing fresh water that has been contaminated by animal urine to come into contact with unheated breaks in skin.It is a highly contagious,deadly disease. Leptospirosis is most common in temperate or tropical climate where it is linked to local infrastructure and poor housing and waste disposal. A case study to map the risk prone zones of leptospirosis in Chennai city by taking the data from Health centres and hospitals, combining with the local terrain analysis has been taken up.