In 4 cases of Alzheimer's disease (AD) a tau antiserum immunostained thin, round or flame-shaped profiles disposed around the nuclei of the cerebellar fusiform-type Golgi cells. In adjacent sections either a Bodian silver method or Congo red failed to reveal any abnormal structures. Since normal tau immunoreactivity is located on axons and is absent in formalin-fixed tissue, the tau-reactive profiles are likely to correspond to small masses of abnormal filaments, antigenically similar to those composing neurofibrillary tangles (NFT). This observation indicates that in AD the NFT formation is more diffuse than that showed with conventional histological methods.