The objective of this project was to describe geriatric care provided under Medicare-risk contracts in HMOs with established Medicare programs. These findings provided the basis for an invitational workshop, sponsored by the National Institute on Aging and the Robert Wood Johnson Foundation, to formulate a research agenda for geriatric care in HMOs. The case study method involved site visits to seven HMOs by a physician with expertise in geriatrics, a managed care specialist, and a program development specialist. Representatives from the HMOs included senior executive officials, physicians recognized for providing and promoting geriatric care, research and program development staff, and various clinical staff including pharmacists, geriatric nurse practitioners, nurses, and social workers. The most frequently encountered geriatric care programs were categorized by the following six objectives: (1) identifying high risk patients, (2) assessing multi-problem patients, (3) treating multi-problem patients, (4) rehabilitating patients following acute events, (5) reducing medication problems, and (6) providing long-term care and home health care. Unique programs identified from these site visits included screening methods for new enrollees, approaches to comprehensive geriatric assessment, use of skilled nursing facilities for intensive rehabilitation and postacute care, and drug profiling and review. Utilization of geriatric nurse specialists and programs aimed at coordination with social services were pervasive in many of these HMOs. Workshop participants proposed several research and demonstration projects in all six areas. Overall consensus emerged that HMOs with Medicare-risk contracts provide a valuable setting for experimentation in geriatric care. Given the current health policy emphasis on managed care and capitated payment methodologies, geriatric care research in HMOs should be a high priority.