Excessive consumption of fluoride leads to toxic manifestations in man, collectively referred to as Fluorosis. Latest estimates suggest that around 200 million people from among 25 nations the world over, are under the dreadful fate of Fluorosis. In India, 20 states are under fluoride attack. OBJECTIVES: To study the prevalence and causative factors of dental fluorosis among children in the age group of 10-15 years in Kerala. METHODOLOGY: Two endemic districts and two neighboring non endemic districts were selected for this study. Sample size of 980 was calculated and adequate sample was selected from the school going children. A pretested modified questionnaire was used to collect the data. The fluorosis status was assessed by dental specialists. The information regarding the fluoride content of the water was also obtained. The data was entered and analyzed. The prevalence of fluorosis was calculated in percentages. RESULTS: The prevalence of dental fluorosis in the endemic districts of Alappuzha and Palakkad were 37.4% and 39.2% respectively. The prevalence in the neighboring non endemic districts of Kollam and Thrissur were 4.4 % and 2.2% respectively. The community fluorosis index was 0.61 in Alappuzha and 0.63 in Palakkad. The prevalence was higher among boys than among girls. CONCLUSION: Dental fluorosis is a public health problem in the districts of Alappuzha and Palakkad in Kerala, India. The main causative risk factor is the increased fluoride content of drinking water. Immediate measures should be taken to defluoridate the water to the optimum level of fluoride in order to solve this public health problem.