We examined 50 patients with parkinsonism-dementia complex of Guam (Guam PDC), 10 Guamanian patients with amyotrophic lateral sclerosis (ALS), 5 patients with combined PDC and ALS (PDC-ALS), and 20 non-PDC non-ALS Guamanians, who had been autopsied between 1979 and 1982, paying special attention to glial inclusions. Gallyas-positive and tau-immunopositive intracytoplasmic inclusions were observed in many of the glial cells, in addition to extensive neurofibrillary tangles (NFTs) in the brains of Guam PDC and PDC-ALS patients. Granular hazy inclusions were seen in the astrocytes, and some crescent/coiled inclusions were observed in the oligodendroglia. Many granular hazy inclusions were observed in the amygdaloid nucleus, inferior olivary nucleus, and lateral funiculus of the spinal cord. The crescent/coiled inclusions were observed predominantly in the anterior nucleus of the thalamus, motor cortex, midbrain tegmentum, pyramids of the medulla oblongata, and lateral funiculus of the spinal cord. The granular hazy inclusions have never been reported previously, and the topographic distribution of the crescent/coiled inclusions in Guam PDC and PDC-ALS differs from those reported previously in other NFT-forming diseases. These findings indicate that Guam PDC and PDC-ALS involve not only neurons but also glia, and that their morphological and topographic differences from other NFT-forming diseases may provide further insights into their distinct etiopathogenesis, and thus prove useful for diagnosis.