Total body calcium was measured in 8 men and 4 women, aged 20–51 years, undergoing kidney transplantation. The initial measurement was made within 8 weeks of operation and subsequent measurements up to 33 months postoperatively. Transplant rejection was prevented by low-dose prednisolone therapy (20 mg/day). 2 patients underwent parathyroidectomy for hypercalcaemia, and their total body calcium increased by 29 g (3%) and 66 g (8%). In the remainder the mean annual change was -0.9% (3.7, SD) over an average follow-up period of 17 months. This fall in total body calcium was statistically insignificant and was smaller than that previously described in patients treated with higher doses of steroids.