Clinical differentiation of neurodegenerative diseases that produce dementia is imprecise. Neuropathology offers the only way to make a definite diagnosis. The CNS autopsy is also important for clinical quality control and for providing tissue that furthers research into these disabling disorders. This brief article summarizes the major neuropathologic features of largely sporadic disorders that present with late-life dementia. The common causes of dementia discussed are Alzheimer's disease, Lewy body disease, and vascular dementia; less common disorders described are dementia lacking distinctive histopathology, Pick's disease, progressive supranuclear palsy, corticobasal degeneration, and Creutzfeldt-Jakob disease.