This is confusing to a lot of people because both programs are administered by the Social Security Administration. Social Security Disability Insurance (SSDI) is a program that workers, employers and the self-employed pay for with their Social Security taxes.

You qualify for these benefits based on your work history and the amount of your benefit is based on your earnings. Supplemental Security Income (SSI) is a program financed through general tax revenues -- not through Social Security trust funds. SSI disability benefits are paid to people who have a disability and who don't own much or have a lot of income.