To understand primary care physicians' concerns about providing care to cognitively impaired elders, we conducted in-depth interviews with 20 physicians. We performed a qualitative analysis based on methods of grounded theory. Physicians described profound changes in both the process of medical care and the doctor-patient relationship. Key issues that emerged included patients' impaired ability to provide accurate history or to adhere to treatment plans and the shift in the goal of care from "curing" illness to "caring" for the patient's quality of life. The doctor-patient relationship changed radically as third parties became involved in care and ethical dilemmas related to patient autonomy and safety were common challenges. The increased complexity and prominent psychosocial issues were difficult to manage, as the practice environment was not structured to provide the support and resources these patients needed. A model of care that embraces the prominent psychosocial aspects of care is badly needed.