Abstract: Assessment of groundwater vulnerability using DRASTIC model in GIS environment has become more widespread for effective groundwater resource management. A study was carried out in Coimbatore south taluk, Tamilnadu, India to develop a empirical model DRASTIC to identify the vulnerability index owing to groundwater contamination with increasing population, industrialization and agricultural activities. The most important mappable factors that control the groundwater potential are depth of water, net recharge, aquifer media, soil media, topography, impact of vadose zone and hydraulic conductivity of the aquifer. Estimation of DRASTIC Index involves multiplying each parameter weight by its rating corresponding to its study area and summing the total. Based on DRASTIC index values it was observed that the vulnerability class in the study area falls between low vulnerability to high vulnerability. The results provide important information for the local authorities and decision making personals for effective management of ground water resource.