Giant cell tumours involving vertebral bodies are still difficult to treat, though results are gradually improving. The object of this study was to assess the results of "complete excision", both of previously untreated giant cell tumours and of recurrences, and to consider the possible effects of any tumour contamination during operation. Nine consecutive patients with giant cell tumours of the thoracic and lumbar spine were treated surgically between 1986 and 1995. Four of these patients were referred with recurrent tumours. All operations aimed at complete resection of the tumour, where possible an en-bloc approach was used. The spines were reconstructed with autografts and instrumentation. All patients were regularly reviewed as part of an on-going study. Following the five operations for previously untreated tumours ("primary" operations), there were no local recurrences, but one patient died of pulmonary metastases. One of the four patients operated upon for a recurrence developed a further recurrence, which was excised 2 1/2 years ago. It would seem that giant cell tumours of the thoracic and lumbar spine, including recurrences, should be treated by complete excision. The en-bloc approach is the safest technique. Where an intralesional component is unavoidable, total removal of the (pseudo)capsule should be ensured by preliminary extralesional dissection. Any tumour spill should be meticulously removed. The use of frozen sections to check resection margins is advisable.