Although there is a broad base of literature on depression among elderly patients and on mania in younger patients, there is a relative paucity of information on bipolar disorder in the elderly population. While the quantities of data reflect the relative prevalences of these illnesses, there is evidence to suggest that classification of mania in the elderly with respect to age of onset, natural course, family history, and pathophysiology may be useful in understanding the heterogeneous etiologies of this syndrome. This paper presents a review of the literature on the incidence and course of illness in late-life bipolar disorder. Further, dilemmas of diagnostic classification in relation to associated risk factors will be discussed.