Twenty-five patients with endocrine tumours (13 with endocrine pancreatic tumours and 12 with carcinoids) were examined with angiography, computed tomography, magnetic resonance imaging and ultrasonography. Seventeen patients had liver metastases and were followed between 3 and 66 months with serial examinations during treatment with chemotherapeutic agents and interferon. The efficiency of the various techniques to detect metastases was investigated. Analysis of changes in tumour size during treatment was made to see if treatment effects could be monitored with radiologic examinations. Ultrasonography was the best non-invasive method for detection of metastases and is recommended as standard method for imaging in this group of patients. Angiography was even better showing extremely small metastases, less than 5 mm, and is recommended in selected cases. With one exception, no significant change in tumour size was noted in spite of clear laboratory and clinical signs of therapy effect indicating that tumour size determination is not useful for therapy monitoring in this type of disease.