Fluorosis of teeth is due to presence of excess fluorine in drinking water. It is specially affected by ingestion of fluoride containing drinking water during the time of tooth formation. Normally, water contains fluorine, at a level of 0.8–1 ppm. If it is more than 1 ppm, it may lead to fluorosis; affected teeth appear chalky white on eruption and later turn brown. The factors determining the severity of fluorosis are amount of fluoride exposure, age of the child during exposure, individual response, genetic factors, weight, nutrition, degree of physical activity and bone growth. Overexposure to fluoride may occur through various sources, some of which include fluoride containing dentifrices or mouthrinses which children are at risk to swallow, bottled or untested package of drinking water for its fluoride content, improper use of fluoride supplements, and public water fluoridation. Various stages of Dean’s fluorosis of teeth have been discussed. Bleeching, defluoridation of water, and cosmetic rehabilitation by artificial crowns and veneers are the treatment options.