The study was undertaken with the objective of assessing vulnerability to climate change in the coastal districts of Tamil Nadu and Puducherry on production of rice. Coastal districts of Tamil Nadu and Puducherry are more sensitive to climate change and most disaster prone districts. Vulnerability is a function of the character, magnitude, and rate of climate change and variation to which a system is exposed, its sensitivity, and its adaptive capacity. For the assessment of the vulnerability index, a total of 22 indicators were chosen, having both positive and negative functional relationships. Data was gathered and normalised so that every indicator or variable could be transformed between 0 and 1. For assigning weights to the variables the Principal Component Analysis (PCA) was used to construct the index . The vulnerability index has was further classified into high, moderate, and less vulnerable zones based on the mean and standard deviation of the index. Among the study districts, Thanjavur (0.11) is the least vulnerable district with the lowest sensitivity (0.28) and highest adaptive capacity (0.60), Karaikal (0.71) is the most vulnerable with the highest exposure (0.55) and lowest adaptive capacity (0.36). Additionally, the outcome reveals that the most vulnerable regions were Karaikal, Nagapattinam, Thoothukudi, Cuddalore, and Pudukottai districts of coromandal coastal districts of southern India .We need to frame policies and implement them according to the vulnerability of regions to climate change for achieving sustainability of rice economy in developing country like India.