The authors review current understanding of manic syndromes and bipolar disorders in the elderly, emphasizing the limited number of systematic studies available. Discussion is focused on the validity of late age at onset as a nosologic distinction in geriatric patients. This issue is contrasted with possible age-associated effects on early-onset illness. Data regarding incidence and prevalence in the elderly are assessed, and the high average age at onset of mania is noted. The review cites evidence that relatively low rates of familial affective disorder and increased frequency of certain diseases and drug use are associated with late age at onset. Aspects of psychopathology in the elderly, course of illness, and outcomes including chronicity, mortality, and cognitive impairment/dementia are considered. Management of these elderly patients is briefly discussed, highlighting questions concerning response to lithium salts.