Care of the aged in the United States by advanced long-term care institutions has resulted in many important contributions to our knowledge of the aging process and disease over the past four decades. These institutions are characterized by well organized medical staffs, with full-time medical directors who also serve as chiefs of the Medical Department and as stimulators and coordinators of research and teaching. These institutions provide comprehensive management, with laboratory, x-ray and necropsy capabilities and multiple levels of care. Many serve as teaching centers and have affiliations with medical schools and university hospitals for house staff and postgraduate medical training. Several contributions to the medical literature on aging are described, among them being the earliest published in this country concerning pneumonia, cancer, arcus senilis, atypical and silent myocardial infarction, digitalis therapy, subacute bacterial endocarditis, calcific aortic stenosis and congenital heart disease. Fundamental papers have been published on a system of functional classification, attitudes toward death and dying, evaluation of mental status, the diagnosis and care of chronic brain syndrome, psychologic evaluation, the diagnosis and care of many ophthalmologic disorders, and the causes, incidence and prevention of accidents among the aged. The long-term care institution, under proper circumstances, is an excellent site for good medical care, and significant contributions to research and teaching.