We reviewed the medical records of eight patients clinically diagnosed with Alzheimer's disease who were found on autopsy to have neuropathologic findings inconsistent with Alzheimer's disease. The clinical criteria for the diagnosis of probable Alzheimer's disease from the National Institute of Neurological and Communicative Disorders and Stroke/Alzheimer's Disease and Related Disorders Association (NINCDS/ADRDA) were retrospectively applied to these patients. The patients presented with clinical features atypical for Alzheimer's disease early in the course of the disease, including focal neurologic findings, gait abnormalities, motor speech abnormalities, and extrapyramidal features. Attention to these clinical red flags may decrease the likelihood of misdiagnosis of Alzheimer's disease in a patient with a non-Alzheimer's disease cause of dementia.