The organic/nonorganic distinction in contemporary classifications of mental disorders such as DSM-III and DSM-III-R has important prognostic and treatment implications, because it directs the clinician to pay special attention to the possibility of an underlying "physical" disorder as the cause of the mental disturbance. However, the term "organic" raises serious and intractable problems, since the connotative meaning of the term always returns to its historical roots, which imply an outmoded functional/structural, psychological/biological, and mind/body dualism. The authors present a proposal being considered for DSM-IV that would eliminate the term "organic" and reorganize the classification of organic mental disorders. Disorders previously referred to as "organic mental disorders" would be renamed as either "secondary disorders" (if they are due to "physical" disorders) or "substance-induced disorders." The entire classification of mental disorders would be reorganized to distribute the secondary and substance-induced disorders into the major groups with which they share phenomenology. The traditional organic mental disorders--delirium, dementia, and amnestic disorder--would be grouped together under the rubric of "cognitive impairment disorders." While acknowledging problems with the suggested new terminology and reorganization of the classification, the authors argue that the potential benefits of the proposal for clarity and for facilitating differential diagnosis justify putting to rest the familiar but now anachronistic term "organic mental disorders."