Discussions of the federal budget often refer to mandatory spending on Social Security, Medicare, and similar programs as "uncontrollable." In contrast with discretionary programs that Congress usually funds with annual appropriations, entitlement spending is determined by permanent laws specifying who qualifies for what benefits. This article examines changes in the percentage distribution of federal outlays since 1962. It highlights the rapid growth in mandatory spending driven by increased spending for health and retirement programs and the contrasting decline in defense spending as a share of total spending.