The aim of this study was to test the hypothesis that diffuse non-metastatic enlargement of the adrenal glands occurs in patients with malignant disease. Measurements of the adrenal glands were obtained from computed tomographic (CT) images in two groups of patients with malignant disease (47 patients with lymphoma and 144 patients with other primary tumours) and a control group consisting of 55 patients without malignant disease. Patients with conditions known to affect the adrenal glands were excluded. Adrenal glands with focal mass lesions, as judged by CT, were also excluded. The following measurements were obtained: the maximum width perpendicular to the long axis of the gland; and maximum width of the medial and lateral limbs. There was a statistically significant difference in all measurements between the control group and the groups with lymphoma and other tumours. No significant difference was demonstrated in the size of the adrenal glands in patients with different stages of malignancy. We have shown that the adrenal glands are enlarged in patients with malignant tumours, including lymphoma. We believe that this enlargement is due to adrenal hyperplasia rather than to metastatic neoplasm.