Chronic fluoride intoxication in the form of osteo-dental fluorosis was investigated in 21 villages of Banswara, Dungarpur, and Udaipur districts of southern Rajasthan, where fluoride (F) concentrations in drinking waters range from 1.5 to 4.0 ppm. Interestingly, a variable prevalence of fluorosis was observed in villages having almost the same F concentrations. At 1.5 ppm, 21.3, 25.6, and 38.9% of children and 33.3, 36.9, and 44.8% of adults in different villages of these districts were found to be affected with dental fluorosis. The maximum prevalence of dental fluorosis (77.1%) was found in the 17-22 year age group. No significant correlation was found between prevalence figures and gender. At this 1.5 ppm F concentration, 6.1, 6.8, and 9.5% of adults in villages of Banswara, Udaipur, and Dungarpur districts, respectively, showed evidence of skeletal fluorosis. Subjects of these districts showed the highest prevalence of skeletal fluorosis, 32.8, 36.6, and 39.2% at maximum F level of 3.7 ppm, 4.0 ppm, and 3.2 ppm, respectively. No children were found affected with skeletal fluorosis or skeletal deformities, the prevalence of which was higher in males and increased with age and higher F level. Deformities such as crippling, kyphosis, and genu varum were observed most frequently in higher age groups (>40 years) at a F concentration of 2.8 ppm or higher. None of the fluorotic subjects showed evidence of goitre (thyroidism) or genu valgum syndrome. Radiological findings of other deformities in fluorotic subjects were also found. Possible factors responsible for a higher prevalence of fluorosis in villages having similar F concentrations are discussed.