A correlative study of incidences of fluorosis and possible fluoride sources in ward in , Region, . Jonas Seiyaroi Metulo Mungure Degree of Master of Science (Biology) University of Dar es Salaam, College of Natural and Applied Sciences, 1984. Skeletal and dental deformations attributable to fluoridic drinking water were reported in Maji ya Chai Ward of Arumeru district, , Tanzania, for the first time between 1950 and 1960. Basing on these reports, the government expended efforts to supply the villagers with less fluoridic water in 1975.In the present study detailed surveys were done to identify sources of fluoride and relate diet quality to Prevalence and severity levels of fluorosis in Kitefu, Kimandafu, Lerai and Olkung’wa do villages. Fluoride concentration and physical properties were determined in water during moderate and high floods. The flowing water systems registered 2.20 to 20 parts per million, ppm, fluoride, whereas stagnant waters registered even much higher values. Generally, Olkung and wado samples showed higher fluoride concentrations, salinity, alkalinity and lower temperatures. High salinity and alkalinity kept off Olkung do villagers from drinking the fluoridic water. Plants showed least contribution to fluorosis. Analysis of foodstuffs showed no significant differences between plant fluoride accumulations among villages. Analysis of local salts showed up to 14, 900 ppm fluoride. These, and the fluoridic water, are the culprits of fluorosis. One thousand six hundred people were observed, interviewed and graded from 0 to 4+ categories of fluorosis. Prevalence and severity levels ranged from 58.1% to 75.8% and 3.7% to 39.3% respectively. The group between 11 - 20 years appears to be the most susceptible to pluorosis. There was no correlation between water fluoride and prevalence levels. The lowest severity and absence of skeletal fluorosis in Olkung wado were due to better diet and dietary habits than other villages Solution to the problem would be to intercept natural sources with non-fluoridio piped water; educating villagers to drink from approved sources; eating balanced diet and a special clinic for fluorosis problems. Otherwise villagers should be shifted to less endemic areas owned by ARUDECO to the west.