In this article, we examined the concentration of Medicare expenditures among the aged for 1969, 1975, and 1982 to determine if expenditures have become more concentrated among a few heavy users of service over time. Despite an increase in reimbursements for the aged from $6.0 billion in 1969 to $41.8 billion in 1982, the distribution of those expenses remained remarkably stable, with a slight lessening in the concentration of reimbursements in 1982. Patterns were similar for both Part A (hospital insurance) and Part B (supplementary medical insurance) services. The concentration of expenditures was much greater among survivors than among people who died in both 1975 and 1982, with little change in the distribution of expenditures within either group.