This study was carried out to determine the effects of fluorosis on plasma fluor (F), serum calcium (Ca), phosphorus (P), magnesium (Mg), calcitonin (CT), intact parathyroid hormone (iPTH) and vitamin D-3 (Vit D-3) in sheep. A total of 75 Morkaraman sheep, 50 with chronic fluorosis (Fluorotic group) from Tendurek Mountain region (altitude about 2000 m) and 25 without any fluorosis (Control group) from Van (altitude 1700m) were used, aged 3-4 years. Data collected 50 sheeps with chronic fluorosis in the in East Anatolia, Van-Agri, Turkey, were compared with data from 25 without any fluorosis sheeps from the Van region. Plasma F levels were measured with spesific fluride electrode, serum Ca, P and Mg levels were photometrically determined; serum CT and iPTH levels were determined using chemiluminescent immunometric assay, serum Vit D-3 level were analysed with HPLC method. Serum P and Vit D-3 levels were lower in fluorotic group than in control group (p<0.001), while serum CT (p<0.01) and iPTH (p<0.001) levels were higher. The differences for Ca and Mg values were found statistically nonsignificant. The results obtained were after a long term exposure of sheep to high amounts of fluorine and supports occurrence of osteomalatic conditions. In conclusion, clean water should be given to animal and people who live in this region because of irreversible pathological situation occurs after fluorosis develops. Otherwise, Ca, P, Mg and Vit D-3 supplementations has to be given at proper doses to prevent negative effects of fluoride on teeth and bones.