Late life depression is common and associated with disability, reduced quality of life, mortality, and high health care costs. Depressed older adults frequently have comorbid medical illnesses and cognitive impairment, but relatively little is known about the diagnosis and treatment of depression in the face of these comorbid conditions. Only a minority of depressed older adults receive specialty mental health care and most depression care is provided in primary care where few receive effective treatment. Very little is known about the epidemiology and quality of care for bipolar disorder in late life. Additional research should focus on the quality and outcomes of care for older adults with affective disorders in diverse settings (including primary care, specialty mental health care, home health care, nursing homes, and assisted living facilities) and on the care of older adults who have affective disorders and comorbid medical disorders, dementia, substance use disorders, or chronic pain.