Social Security provides benefits to nearly 9 million disabled workers, a quarter of a million disabled widows and widowers, and about a million adults whose disabilities began in childhood. Two policy challenges regarding Social Security are benefit adequacy and trust fund sustainability. We describe how beneficiaries receiving Social Security for disabilities vary as well as the implications of these differences for beneficiaries' incomes and service needs and for proposed changes to Social Security. We examine gender, age at disability onset, family circumstances, impairment type and severity, and health care and long-term service needs.