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Increase blood level of thyroid hormones due to hyperthyroidism can change the balance between resorption and bone formation and result in hypercalcemia, increase Alkaline Phosphatase and increase in urinary Calcium excretion. Due to these finding and the nutritional conditions of our country in Calcium containing food, we decided to evaluate some of bone indexes in hyperthyroid patients. 30 women, 6 men between 17-40 years (23 patients) and more then 40 years (13 patients) were the sample populations. The control subjects were 35 healthy people 17-40 years (25 persons) and more than 40 years (10 persons). The serum Calcium, phosphorus and Alkaline Phosphatase were determined in these hyperthyroid patients. There were a meaningful correlation between the Alkaline Phosphatase of hyperthyroid patients compared to normal subject (P<0.05) in the patients more than 40 years old, and (P<0.01) in the 17-40 years patients. There were no differences between serum Calcium of hyperthyroid patients and normal subjects. The results from this investigation indicate that in hyperthyroid patients the average Alkaline Phosphatase level is higher than normal subjects. On the other hand the reason for not having a meaningful differences in Calcium level between the hyperthyroid patients and normal population may be due to low dietary intake of dairy produce and proteins in daily diet, which results in low amount of Calcium in nutrition.