IRS Letter 566: You're Being Audited by Mail — What to Do
Letter 566 is how the IRS starts a correspondence audit. It's an audit by mail, focused on specific items on your return, and how you respond shapes the outcome.
Have a CPA review my Letter 566Letter 566 means your return was selected for examination. The IRS lists the items it's questioning, such as deductions, credits, or income, and asks you to send documentation by a specific date.
Most mail audits are limited to a few items. A clear, organized response with the right documents often ends the exam with little or no change. A missed deadline usually ends it with the IRS disallowing the items.
Where this notice falls in the IRS process
- Return filed
- Letter 566 — audit begins — you are here
- You send documentation
- Letter 525 or report — proposed changes (if any)
- Agree, or appeal within 30 days
What the IRS can do now
- Ask for receipts, statements, and other proof for the items listed.
- Propose changes to your tax, plus interest and possibly penalties, if items aren't supported.
- Expand the exam to other items or years if it finds related issues.
What the IRS generally can't do yet
- Make the changes final without giving you a chance to respond and to appeal.
- Refuse to let you have a representative. A CPA, EA, or attorney can handle the audit for you with a power of attorney.
Your options
Respond with documentation
Send only what's requested, organized by item, with a short cover letter. Keep copies of everything.
Get representation
A CPA can handle all contact with the examiner, which keeps the scope focused.
Ask for more time
If you need longer to gather records, request an extension before the deadline.
Request a meeting
If the issues are complex, you can ask to move the exam to an in-person or phone format.
What not to do
- Ignore it. A missed deadline usually means the IRS disallows the items in question.
- Send everything you have. Extra documents can raise new questions.
- Mail originals. Send copies and keep the originals.
- Guess or reconstruct records without saying so. Be accurate and upfront.
Got a Letter 566? Don't face the audit alone.
Tiffany V., CPA can review what's being questioned, organize your documentation, and deal with the examiner directly.
Book my CPA reviewFrequently asked questions
Is Letter 566 a real audit?
Yes. It's a correspondence audit, meaning it's handled by mail. It's usually limited to specific items on your return.
How long do I have to respond to Letter 566?
Use the date printed on the letter, often about 30 days. Call before then if you need an extension.
What happens after I respond?
The IRS reviews your documents. You'll receive either a no-change letter or a report proposing changes, often with Letter 525, which gives you 30 days to agree or appeal.
Can a CPA handle my audit?
Yes. With a signed power of attorney (Form 2848), a CPA can communicate with the IRS for you and respond on your behalf.
Written by Tiffany V., CPA, founder of Cents Savvy LLC. Last reviewed October 2026. This page is general information, not tax or legal advice for your situation. Cents Savvy LLC is a private CPA firm and is not affiliated with the IRS. Always follow the dates printed on your own notice.