(AFDC), U.S. federal social welfare legislation designed to work with similar state programs to provide financial support for dependent children living with relatives; authorized under Title IV of the Social Security Act of 1935 and subsequent amendments; administered by Department of Health and Human Services; states decide upon eligibility; adults responsible for children may be required to seek employment; all payments must be used to benefit children, not adults, in family; by 1991 had become the single most costly U.S. government welfare program.