If an applicant is approved for SSI/SSDI, will they lose their medicaid and be placed on medicare? If they can have both, which would be their primary insurance?

If a person is approved for both SSI and SSDI they will maintain Medicaid because SSI benefits include Medicaid. However, some states require a separate Medicaid application, (https://www.ssa.gov/disabilityresearch/wi/medicaid.htm).

Medicaid coverage for services varies from state to state. Here is a link that will take you to your state's Medicaid agency: https://www.medicaid.gov/about-us/contact-us/contact-state-page.html.

SSDI benefits include Medicare, but there is typically a 24 month waiting period before the SSDI beneficiary can begin to have Medicare coverage (see Page 12 at https://www.ssa.gov/pubs/EN-05-10029.pdf).

Once the beneficiary has both Medicaid and Medicare, Medicare is typically the primary insurance.