Social Security Disability Insurance (SSDI) provides cash payments and medical coverage to those who are unable to work due to a medical condition that is expected to last at least 12 months or result in death. SSDI is a federal insurance program funded by payroll taxes and managed by the Social Security Administration. To be eligible, applicants must be 18 or older, not currently receiving benefits on their own Social Security record, unable to work due to a qualifying medical condition, and not have been denied disability benefits in the last 60 days. The application process involves providing information about one's medical condition and work history.