Supplemental Security Income (SSI), which policymakers created in 1972, provides monthly cash assistance to people who are at least age 65 or are disabled and have little income and few assets. SSI benefits are critical for those who need them — but SSI is woefully out of date, leaving many people in need ineligible for benefits and others who receive them without enough resources to meet basic needs. Policymakers need to update SSI’s rules in a variety of ways. Its maximum benefit is only three fourths of the poverty line, and 4 in 10 recipients have incomes below the federal poverty line even with their SSI benefits. Its income and asset limits have not been updated for decades. These rules allow recipients to keep only a meager amount of their earnings, other benefits, and savings, and prevent many older and disabled people in need from qualifying. SSI also excludes most immigrants (until they become U.S. citizens) and residents of U.S. Territories, most of whom are people of color. SSI’s complex and intrusive rules make it more expensive to administer and burdensome for applicants and beneficiaries. The Social Security Administration (SSA) spends more to administer SSI than it does to administer the much bigger Social Security Disability Insurance (SSDI) program. Policymakers can strengthen SSI by expanding and simplifying it. They should update its asset limits and income rules and automatically adjust them. They should raise its basic benefit, exempt retirement savings from the asset limits, and ease eligibility restrictions for immigrants and residents of the territories. And, they should repeal some of its complex and intrusive rules.