Planning is being initiated for the American Psychiatric Association's Diagnostic and Statistical Manual of Mental Disorders 5th ed. (DSM-V). Therefore, the dementia diagnosis criteria in the American Psychiatric Association's DSM-IV-TR (4th ed, text revision, 2000) have been compared with the World Health Organization's International Classification of Diseases (10th revision, 1992). Critiques are based primarily on (a) internal consistency and validity of the classification, (b) historical development of the field, (c) conclusions of consensus conferences, and (d) current knowledge and practice. It is suggested that (1) the entire category be labeled "cognitive disorders," to better characterize this group of disorders, (2) there is no longer any scientific basis for the presenile versus senile dementia dichotomy at age 65, (3) Alzheimer's disease no longer should have unique status as a "diagnosis of exclusion," (4) future manuals should incorporate knowledge regarding the clinical manifestation and course of Alzheimer's disease and other dementias, and (5) the classification "Pick's disease" should be broadened to "frontotemporal dementias." DSM-V should incorporate continuing advances in the neuroscience knowledge base and understanding of these disorders.