Frequency of complications in thyroid surgery is evaluated in a series of patients treated during a recent period lasting one year (1997). The records of 455 patients consecutively operated on were analyzed: 396 patients were affected by benign disordes and 59 by thyroid carcinoma. Total thyroidectomy was performed in 158 cases, near subtotal thyroidectomy in 94, thyroid totalization for recurrent disease in 21 and lobectomy in 182 ones. Post-operative haemorrhage, such to require surgical re-exploration of the thyroid bed, occurred in 2 patients (0,4%), both after total thyroidectomy for hyperfunctioning goiter. Recurrent laringeal lesion has been observed in 2 patients (0,4% of all patients), both after total thyroidectomy for cervico-media-stinal goiter. Transient hypopara thyroidism occurred in 48 patients (10,5%), while definitive one in 9 (1,9%), of which 5 after total thyroidectomy, 2 after subtotal thyroidectomy and 2 after reoperation. Haemorrhage nearly always occurs in the first postoperative hours and gravity is conditioned by tracheal compression exercised by the haematoma. An aspirative drainage located in thyroid bed and a not hermetic closure of the middle line help a precocious diagnosis and sometimes avoid a surgical re-exploration. Some technical surgical devices permit to reduce the risk of inferior laryngeal nerve palsy. Hypoparathyroidsm, often transient, is a complication of bilateral thyroid surgery, but unavoidable when more extensive thyroid surgery is required.