The study of long term agricultural drought becomes essential for monsoon dependent countries like India in order to identify the drought prone areas and develop various strategies to improve the agricultural productivity in the country. The present study attempted this by assessing the long term agricultural drought for a period of 20 years from 1984 to 2003 for the State of Tamil Nadu, India using one of the popular indexes called Normalized Differenced Vegetation Index (NDVI) anomaly. The NDVI from Global Inventory Modeling and Mapping Studies (GIMMS) which is an open source data, has been used in the present study to compute the NDVI anomaly. The agricultural drought intensity maps prepared using NDVI anomaly will help the state government authorities to identify the drought risk areas and prioritize their actions based on the severity of the drought level. The result showed that the State experienced moderate to severe drought situation during most of the years in the analysis period of 1984 to 2003. The drought affected area and its percentage in the entire state during the study period confer the fact that the current drought condition of the state could have been foreseen two decades back and hence enabled the agrarian society to be precautionary. The recurrent drought in the state necessitates the Government to take suitable preventive measures to avoid drought in future.