Three million persons under age 65 are entitled to Medicare because of disability. This study examines their Medicare use and mortality. Disabled enrollees had higher health care use and mortality than comparison groups of Medicare's aged enrollees or of the general population under age 65. One type of disabled enrollee, adults disabled as children (over one-half of whom are mentally retarded) show lower use rates than the other types of enrollees--workers and widows. High mortality of the disabled during the 2-year waiting period for Medicare suggests the need to investigate how they pay for care during this period.