We studied the prevalence of hypercalcaemia in 34 Chinese patients with pulmonary (n = 32) or miliary (n = 2) tuberculosis. None of these subjects were given vitamin D or calcium supplements. Plasma calcium levels were measured at presentation and at 1- to 2-monthly intervals after treatment. During the 6-month study period, two patients (6%) developed hypercalcaemia (plasma calcium greater than 2.51 mmol/l), as compared to figures of 16% to 28% in the United States and India. By correcting the plasma calcium to a normal albumin, five (15%) of our patients were hypercalcaemic, as compared to a figure of 48% in Greece. Apart from variations in methodology, discrepancies in the reported prevalence of hypercalcaemia in tuberculosis may be due to differences in sun exposure, and vitamin D and calcium intake.