Ninety-one patients with histologically proven anaplastic carcinoma of the thyroid were referred to the Beatson Oncology Centre between 1961 and 1986. The female:male ratio was 2.4:1 and the median age at presentation was 70 (range 38-92) years. All patients had a thyroid mass at presentation and the most common symptoms were dyspnoea, dysphagia and dysphonia. Five patients had a total thyroidectomy and 28 partial thyroidectomy. Ninety five per cent of patients received external beam radiotherapy. Results show dyspnoea to be the only symptom strongly influencing survival. Total or partial thyroidectomy is associated with increased survival. This association is most marked for patients presenting without dyspnoea. Eighty per cent of patients responded to radiotherapy.