Health care of the highest quality promotes successful aging. This paper examines the efforts that have been taken to improve the quality of health care, especially hospital care. Most of these efforts have evaluated conventional treatments of specific diseases; they are critical but underfunded and underused, and many practices persist without much evidence of efficacy. Fewer efforts have attempted to improve care for groups of persons in specific settings, such as the hospital. Three complementary approaches to improving comprehensive outcomes for hospitalized older persons-Geriatric Evaluation and Management, Acute Care for Elders, and the Elder Life Program-demonstrate what has been learned about improving care for older persons by redesigning microsystems of care. A research agenda for advancing successful aging should include specific actions to improve the quality of health care.