Abstract: ObjectiveTo determine the prevalence of endemic fluorosis in Dali county, Shaanxi province. MethodsStratified random sampling was performed in 20 administrative villages of eight towns to assess such conditions as dental fluorosis among 8 to 12-year-old children, clinical and X-ray skeletal fluorosis among adults over the age of 16, fluoride content in drinking water and fluoride content in urine of children in Dali in 2008. ResultsIn the twenty administrative villages investigated, the prevalence of children dental fluorosis was 41.74% with the defect rate of 1.3%. The dental fluorosis index reached 0.92. The positive rate of skeletal fluorosis among adults over the age of sixteen was 20.67%; and X-ray positive rate 61.68%. A total of 100 water samples resulted in a fluoride content exceeding the national standard ( 1.0 mg/L), the lowest water fluoride 1.36 mg/L with a maximum of 6.99 mg/L. The geometric mean urinary fluoride among children reached 3.95 mg/L, 92.12% of children having urinary fluoride above the normal upper limit (1.50 mg/L). ConclusionThe prevalence of endemic fluorosis associated with drinking water was severe in Dali county. Therefore, water-improvement-based comprehensive prevention and treatment efforts shall be made.