Temporary post-thyroidectomy hypocalcaemia is a relatively common complication, due to removal, injury or devascularization of the parathyroid glands. It may also be secondary to hungry bones due to postoperative reversal of thyrotoxic osteodystrophy, reactive hypoparathyroidism due to relative hyper-calcaemia in thyrotoxic patients or calcitonin release due to operative manipulation of the thyroid glands. 62 patients, 38 with nodular toxic goitres and 24 with simple nodular goitres, undergoing subtotal thyroidectomies were included in this study. 88.7% had at least three parathyroid glands preserved. All had postoperative levels of parathyroid hormone measured. The incidence of biochemical hypocalcaemia was 42% and that of symptomatic hypocalcaemia was 24%. No patient was hypoparathyroid. The incidence of hypocalcaemia was 50% (19/38) in the toxic group compared with 16.6% (4/24) in the simple goitre group. Hypoparathyroidism may not be the cause of post-thyroidectomy hypocalcaemia and ‘hungry bone syndrome’ could be considered particularly in toxic patients