Psychiatric evaluation was performed routinely in 262 patients newly admitted to a Medical Geriatric Evaluation Unit (GEU). The study was conducted in a medical facility that provides excellent medical and surgical care for acute illnesses. The psychiatric disorders found far exceeded those one might expect in a comparable general population, and most were not recognized prior to the patient's transfer. For example, in the GEU, the incidence of organic brain syndrome was 65.3 percent, and of dysphoria-depression 31.3 percent. The data indicate a need to recognize psychiatric problems in order to ensure appropriate care, and suggest that medical care of the elderly with acute illness will be inadequate if it is based upon the approach used for younger populations. This situation apparently exists in most hospitals, including leading medical centers. The needs of the elderly with acute illnesses are quite different from those of younger patients. Recognition of factors that potentially influence outcomes and overall future health will meet public health's primary and secondary prevention goals.