A simple and reproducible method for cryopreservation of brain tissue from patients with Alzheimer's disease is described. Fresh brain slices (1 cm thick) obtained less than 6 h postmortem are placed in sealed plastic bags, sandwiched between 0.3-cm-thick aluminium sheets, and frozen by placing the entire "sandwich" between layers of dry ice pellets. The frozen brain slices are stored at -85 degrees C. Specific anatomic areas can be retrieved at any time for light and electron microscopic, immunocytochemical, autoradiographic and neurochemical studies.