Summary: The budget object classification structure presents budgetary information in terms of the items of government expenditures--the personal and contractual services obtained, capital assets acquired, and other charges and payments. During fiscal years 1971-94, object class obligations trends mirrored the better known trends seen in federal outlays. For example, gross obligations for interest charges and "transfer payments," such as grants and social and health insurance, have grown at about twice the rate of the U.S. gross domestic product. Correspondingly, gross obligations of what remains--what could be called the "operating expenses" of the federal government--represent a declining share of total obligations and have shown overall growth rates of less than one-half the pact of gross domestic product growth. Within this category of obligations, only a few object classes--benefits to current and former personnel; rent, communications, and utilities; and consulting and other services--have experienced real growth greater than the overall pace of economic growth during the 24-year period studied in this report.