Dibrugarh district of Assam is famous for tea production. Major area of the district is covered by large number of small and big tea gardens. Tea gardens use huge amount of fertilizers and pesticides, which are potential sources of fluoride. We, in this study, monitored the fluoride level and some other parameters of groundwater of a large area occupied by different types of small and big tea gardens of Tengakhat revenue circle and another nearby area of Naharkatia revenue circle in which there is no tea garden. Fluoride level in the groundwater of tea garden area is found slightly greater than another area.