In this first part of a two-part article, we review the prevalence of, costs associated with, and treatments for Alzheimer's disease and related dementias, a leading cause of disability in the elderly. New, innovative, and costly drugs to combat dementia are being introduced, causing pharmacy costs to rise. These new drugs, however, may reduce overall medical costs and improve the quality of life of patients with dementia and their caregivers. Issues of cost, excessive service utilization, and quality of life will have significant impact on managed care organizations in the near future as the rapidly aging population experiences significant disability and illness related to dementia. In the second part of this article, we describe the framework for a disease management program for patients with dementia, similar to programs in existence for diabetes and other chronic diseases, that could enable managed care organizations to effectively care for these patients.