If you are in default on your student loans, your income tax refund can be seized, or offset, to pay back your loan. The Treasury Offset Program (TOP) was established to collect delinquent debts owed to federal and state agencies. This would includes the Department of Education which likely backed your student loan. They also collect past due child support payments, income taxes, social security payments and other agency owed debts. Your tax refund isn't the only money it can seize. It also takes wages, retirement, social security benefits and other federal payments.
If you are in good standing with your student loan, you have no need to worry. If you have received a notice or letter of default, read it carefully. The lender is required to give you a 60 day prior notice intent to offset. There will be instructions about a request to avoid offset of your refund. You can make the request in writing or you can call 800-304-3107 to request a review.