Background: Under current law, most Social Security Disability Insurance (SSDI) beneficiaries are not eligible for Medicare until 29 months after the Social Security Administration determines the onset of their disability. During this waiting period, qqqgt;1 in 5 lacks health insurance. This study investigated the effects of providing health care benefits on the health, employment, and other services of uninsured beneficiaries. Methods: New SSDI beneficiaries without health insurance were randomly assigned to receive health care benefits, health care benefits plus additional supports, or a control group. Results: Compared with a control group, those provided health care benefits used more health care, had fewer unmet medical needs, spent less out of pocket on health care, and reported improved health. In addition, those provided the additional supports were more likely to look for work, but the supports did not affect work or SSDI benefits at this very early period. Conclusions: The results provide rigorous evidence that health care benefits can increase health care use and health outcomes. Longer-term follow-up is needed to fully assess the program’s effects on its ultimate benefits and costs, including its long-term effects on health, employment, and benefit receipt.