If you think you may qualify for Social Security's Supplemental Security Income (SSI) benefits, you should fill out an online disability report and then call your local Social Security Administration (SSA) office to complete your application.  (If you cannot complete the online disability report, your local SSA office can assist you with the entire application.) 

Most states supplement the federal SSI payment with payments of their own. Some of these states have the federal government administer their supplemental payment programs and other states administer the supplements themselves.  If your state manages its own supplements, you may have to apply for the supplement at your local county social welfare office.  

When you apply for SSI, you will need to provide the SSA with proof of age and citizenship or legal residence, and you will also have to provide detailed information about your family's financial situation. Usually, an SSA claims representative interviews you and completes the application using the information that you supply.

You should apply as soon as possible so that you do not lose benefits. If you call SSA to make an appointment to apply, SSA will use the date of your call as your application filing date.

If your application is denied, you can appeal. The appeals process is similar to that for appealing Social Security claims denials, and follows several administrative steps. The first step is an administrative reconsideration, which is administered locally.  If you are unsuccessful, you can apply for a hearing in front of an administrative law judge.  If the judge denies your request for reconsideration, then an appeals council will review your appeal.  Those applicants who don't win at this level must file a complaint in federal court for further review.  For a more detailed description of the appeals process, click here. 

Once you begin receiving benefits, the SSA reviews your SSI eligibility every one to three years.