Numerous enlarged neurites and presynaptic terminals containing tubulovesicular profiles of smooth endoplasmic reticulum (SER) were observed in frontal biopsies from six patients with Alzheimer's disease. These accumulations of SER probably reflect disturbances of axoplasmic flows. In addition, curvilinear tubular inclusions similar to those characteristic of Farber's disease were found in one patient. Finally, accumulation of glycogen within neurites and enlarged mitochondria were observed in all patients.