Hypercalcemia has been known to be associated with tuberculosis. In some studies it has been reported to occur commonly. It seems that the studies in which tuberculosis was complicated by hypercalcemia were retrospective and therefore the other causes of hypercalcemia could not be excluded. We have a great deal of experience concerning tuberculosis and have not seen a patient with hypercalcemia due to tuberculosis itself. Therefore we aimed to investigate whether tuberculosis really cause hypercalcemia in a prospective study. We evaluated 104 patients with tuberculosis aged between 14-85 (mean +/- SD 38.5 +/- 15) years, 73 males and 31 females, and 50 age-matched healthy subjects aged between 19-70 (mean +/- SD 39 +/- 13) years, 33 males and 17 females. No significant differences between the patients and healthy subjects were detected in terms of 250HD3, calcium and phosphate levels. Albumin levels were significantly higher in the control group than in the tuberculous group (p < 0.02). No significant difference was found between the calcium levels measured before the therapy (2.4 +/- 0.1 nmol/L) and after the therapy (2.4 +/- 0.2). We think that patients with tuberculosis are not at risk for hypercalcemia either before or during treatment and the development of hypercalcemia as a result of tuberculosis is rather doubtful and needs to be clarified.