The following report using light and electron microscopic and immunological techniques is based on a series of 19 Burmese patients who died of cerebral malaria. The principal change was blockage of cerebral capillaries by Plasmodium falciparum-infected erythrocytes. Ring hemorrhages and segmental necrosis of cerebral capillaries were common. Cerebral edema was variable in these cases. Electrondense knobs, 40 x 80 nm in size, which protruded from the membrane of infected erythrocytes, formed focal junctions between endothelial cells and erythrocytes. These junctions resulted in the entrapment of erythrocytes and caused blockage in the capillary lumen. Immunoperoxidase study revealed that P. falciparum antigens and IgG deposits in the capillary basement membrane. This implies that damage to the cerebral capillary could be related to immune mechanisms.