The Medicare Prescription Drug, Improvement and Modernization Act represents the most far-reaching and one of the most controversial reforms of the Medicare program since its enactment in 1965. The Act ushers in a new Medicare prescription drug benefit, revitalizes Medicare Advantage plans and promotes new approaches to care of Medicare beneficiaries with chronic illness. However, while the Act evidences a commitment to improving the care of beneficiaries with chronic illness, reform may prove elusive. The basic benefit design is daunting in its complexity and for certain beneficiaries, coverage may be less generous and less comprehensive than currently available coverage. To ensure appropriate transition and treatment for dual eligibles and others with chronic illness, both Congress and the Department of Health and Human Services must be prepared to address a number of important benefit design and operations issues and be willing to make mid-course corrections and adjustment as the process unfolds.