This paper presents the clinical features and problems in the management of 34 patients with substernal goitre. Complete evaluation of the mediastinum relied on computed tomography. Thyroid function tests were performed routinely and showed a clinically underestimated incidence of hyperthyroidism (44 per cent). The incidence of occult malignancy in substernal goitres was high (12 per cent). In the majority of patients (88 per cent) the substernal goitres were removed by a collar incision. Four cases of goitres located in a retrotracheal position required a combined cervical and sternotomy approach. None of the 34 patients died. Transient postoperative hypocalcaemia was found in 41 per cent of our patients. The presence of a substernal goitre is an indication for resection based on the risk of malignancy, the risk of acute respiratory distress, the high incidence of thyrotoxicity and a low surgical morbidity.