My sponsor signed an affidavit for me. Will they have to repay benefits I use?

Sometimes, and this is a genuinely different question from whether benefits affect your own green card.

Form I-864 is a contract with the U.S. government, not a formality. If you receive a federal means-tested benefit, the agency that paid it can ask your sponsor to repay it, and can sue them for the cost plus legal fees if they refuse.

Which programmes are covered

The federal means-tested benefits that carry this obligation are SNAP, Medicaid, SSI, TANF, and CHIP. States decide separately which of their own programmes count.

Which are excluded

The exclusions matter more than people expect, and they are written into the statute rather than left to discretion:

• Emergency Medicaid
• Short-term, non-cash emergency relief — disaster assistance
• School lunch and child nutrition programmes, which is where WIC sits
• Immunisations, and testing and treatment for certain conditions

So the programmes most often needed by a family with young children — WIC, school meals, vaccinations, emergency care — do not create a repayment claim against a sponsor at all.

When the obligation ends

It runs until you become a U.S. citizen or are credited with 40 quarters of work, which is about ten years. Your own work counts, and so does work by a spouse during the marriage. It also ends if you die or permanently leave the country. Divorce does not end it.

What this means in practice

Enforcement against sponsors is uncommon but real, and the possibility is enough to make families turn down help they qualify for — including, often, help for children who are U.S. citizens and whose benefits are assessed against them rather than against you.

If your sponsor's exposure is the thing stopping you from applying, get the question answered properly for your own case: whether your sponsor signed an I-864 at all, which programme you are considering, and whether your state counts it. An immigration lawyer or accredited representative can answer that in one conversation.