Among the elderly, bipolar disorder is a significant public health problem, often leading to functional impairment and substantial use of health care resources. There has been a growing awareness regarding the manifestations of bipolar disorder among older adults owing to both changes in national demographics and developing sophistication in the treatment of bipolar illness. Bipolar disorder accounts for 5% to 19% of mood disorder presentations in the elderly, although a clear picture of the exact prevalence of bipolar disorder among older adults in the community is still lacking. Data from treatment centers give a somewhat unreliable picture of the true prevalence and manifestations of bipolar disorder in the general population as elderly patients tend to underuse mental health systems, under-report psychiatric symptoms, and are often treated in nonhospital/clinic settings, such as nursing homes. Factors of particular relevance in late-life bipolar disorder include age of onset, symptom presentation/recognition, secondary mania, psychiatric and medical comorbidity, and response to treatment. Future mental health services research must further explore these issues to optimize care for older adults with bipolar disorder.