How to Respond to an IRS Audit: Step-by-Step Guide for Small Business Owners

Q: What should you do when you receive an audit notice?

Step 1: Read the notice carefully. The notice identifies the tax year, the specific items under examination, and the deadline for response. Don't ignore it. Ignoring an audit notice results in the IRS assessing additional tax based on their proposed changes (with no opportunity to present documentation). Step 2: Gather documentation for the specific items requested. If the IRS questions $15,000 in vehicle expenses, gather the mileage log, fuel receipts, insurance statements, and maintenance records. Don't send everything you have; send only what is requested.

By Yarik Yarosh, CPA ·September 5, 2026 ·4 min read

Written by Yarik Yarosh, CPA (US & Canada) September 5, 2026 · FL CPA license AC61704 · CPA Ontario

Receiving an IRS audit notice is stressful, but it isn’t a criminal investigation. Most small business audits are correspondence audits (conducted entirely by mail) that request documentation for specific items on the return. The business owner’s response, quality of records, and representation determine whether the audit results in no change, a small adjustment, or a significant additional tax assessment.

✓Key takeaway

Types of IRS audits (from least to most serious):

Correspondence audit (CP2000 or Letter 566): Conducted by mail. The IRS identifies a specific discrepancy (unreported income, unsupported deduction) and asks for documentation. Most Schedule C audits start here. Response deadline: typically 30 days.
Office audit: The taxpayer or their representative meets with an IRS examiner at an IRS office. The examiner reviews documentation for specific items. More thorough than correspondence but still targeted.
Field audit: An IRS revenue agent visits the taxpayer’s place of business. Reserved for larger businesses, complex returns, or cases where the IRS suspects significant underreporting. The agent may review books, records, bank statements, and interview the taxpayer.

Your rights during an audit:

The right to be represented by a CPA, enrolled agent, or tax attorney (you do NOT need to attend)
The right to know why the IRS is asking for information
The right to appeal any IRS determination you disagree with
The right to privacy and confidentiality
The right to a fair and just tax system (Taxpayer Bill of Rights, IRC 7803(a)(3))

What should you do when you receive an audit notice?

Step 1: Read the notice carefully. The notice identifies the tax year, the specific items under examination, and the deadline for response. Don’t ignore it. Ignoring an audit notice results in the IRS assessing additional tax based on their proposed changes (with no opportunity to present documentation).

Step 2: Gather documentation for the specific items requested. If the IRS questions $15,000 in vehicle expenses, gather the mileage log, fuel receipts, insurance statements, and maintenance records. Don’t send everything you have; send only what is requested. Volunteering unrelated information can open new issues.

Step 3: Consider representation. A CPA or enrolled agent can respond to the audit on your behalf. They have experience with what the IRS expects and can present documentation in the most favorable light. They can also negotiate adjustments, propose alternatives, and handle the examiner’s questions without the risk of the taxpayer saying something that opens additional issues.

Step 4: Respond before the deadline. If you need more time, call the number on the notice and request an extension. The IRS typically grants 30-day extensions.

Hypothetical example

Round numbers. A sole proprietor receives a correspondence audit notice questioning $20,000 in Schedule C deductions:

$8,000 in vehicle expenses
$5,000 in home office deduction
$7,000 in “other expenses”

Good response (with documentation):

Vehicle: mileage log showing 12,000 business miles x $0.67/mile = $8,040. Provide the log (dates, destinations, business purposes).
Home office: 200 sq ft dedicated office in a 2,000 sq ft home. Total home expenses of $30,000 x 10% = $3,000 (actual method), or 200 sq ft x $5 = $1,000 (simplified). Provide photos of the dedicated office space and home expense records.
Other expenses: itemized list with receipts for each item (software subscriptions, professional development, office supplies).

Result: The examiner accepts the vehicle and office deductions with documentation. The “other expenses” are partially allowed ($5,000 supported, $2,000 disallowed for lack of receipts). Additional tax: $2,000 x 32% = $640 plus interest.

Bad response (no documentation): The IRS disallows all $20,000 in deductions. Additional tax: $20,000 x 32% = $6,400 plus SE tax ($20,000 x 15.3% = $3,060) plus accuracy penalty (20% of underpayment = $1,892) plus interest. Total: approximately $12,000+.

Illustrative numbers only, not a real client and not advice for your facts.

What if you disagree with the result?

If the audit results in a proposed adjustment you disagree with, you have the right to appeal. The IRS Appeals division is independent from the examination function and can settle cases based on the “hazards of litigation” (the likelihood the IRS would win if the case went to court).

The appeal process: (1) File a written protest within 30 days of the examination report. (2) An Appeals officer reviews the case independently. (3) If Appeals cannot resolve the issue, the taxpayer can petition the U.S. Tax Court (before paying the assessed tax) or pay the tax and sue for a refund in District Court or the Court of Federal Claims.

Most small business audit disputes are resolved at the Appeals level without going to court.

Related guides:

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Cite this page

Yarik Yarosh, CPA. "How to Respond to an IRS Audit: Step-by-Step Guide for Small Business Owners." Blue Cloud CPA, September 5, 2026. https://bluecloudcpa.com/guides/small-business-irs-audit-response-guide

This guide is general information, not tax advice for your specific situation. Which points apply, and how, depends on your facts.