Cytoplasmic fine fibrillar inclusions with properties of amyloid occur as neurofibrillary tangles in the brain and in the aging choroid plexus. In the present study we show that inclusions, similar but not identical to those in the choroid plexus, are common in the adrenal cortex of elderly persons. The inclusions consist of aggregates of parallel fine fibrils, often in contact with lipid droplets and partially limited by a membrane. The inclusions have affinity for Congo red and exhibit a bright green birefringence after this staining. Therefore, the inclusions can be regarded as a form of senile amyloid.