OBJECTIVE To evaluate the risk of hypocalcaemia (transient or permanent) after total thyroidectomy for bilateral, benign, multinodular goitre, the frequency and impact of unintentional parathyroidectomy, and the value of parathyroid gland autotransplantation during thyroid surgery. METHODS This was a retrospective study of 351 surgical patients who had undergone total thyroidectomy for bilateral, benign, multinodular goitre over a seven-year period. The primary endpoint was serum calcium concentration immediately post-operatively and during follow up. Normal serum calcium concentration was defined as 2 mmol/l. Parathyroid data were collected during surgery and histological examination. RESULTS In 62 per cent of cases, no hypocalcaemia had been observed after surgery. In 35 per cent of cases, transient hypocalcaemia had been observed after surgery. In 3 per cent of cases, chronic hypocalcaemia had been present six months after surgery. Permanent hypoparathyroidism had been diagnosed two years after surgery in 1.4 per cent of cases. Unintentional parathyroidectomy had been detected in 5.2 per cent of cases. Parathyroid gland autotransplantation had been performed in 7 per cent of cases during surgery. CONCLUSIONS Permanent hypoparathyroidism is rare, although transient hypoparathyroidism occurs relatively frequently. Unintentional parathyroidectomy and parathyroid gland autotransplantation do not affect serum calcium levels.