The findings obtained by morphological investigation of the adrenal glands from 23 patients with cystic fibrosis (CF), have been compared with the findings in 46 controls. In 14 patients with CF, changes in the form of necrosis and/or haemorrhage in the permanent cortex were found and, in addition, in 3 of these there was an accumulation of lipid. The changes were independent of age. In 8 control patients, similar changes localized to the same site were found, but almost exclusively in older children. No correlation was found between these changes and the clinical course of the disease. A number of different investigations suggesting changes in the steroid metabolism in CF are reported.