A Warsaw-based software company receives an official letter from the Krajowa Administracja Skarbowa (National Revenue Administration, KAS) announcing the opening of a tax audit. The finance director has never been through one. The company's accountant is unsure which documents to gather first. The founding partner is asking whether personal liability is a real risk. Three people, three different fears – and all of them entirely justified.

A KAS tax audit is a formal examination of a taxpayer's compliance with Polish tax obligations, conducted by the National Revenue Administration under the Ordynacja podatkowa (Tax Ordinance). The audit may cover corporate income tax (CIT), value-added tax (VAT), transfer pricing, or any other area flagged by KAS risk-analysis systems. Taxpayers generally have 7 days from receipt of the audit authorisation to prepare initial documentation, and the standard audit period may last up to 12 months – though extensions are possible.

This guide walks through the four stages of a KAS audit: the opening procedures, the documentation phase, the findings and appeal process, and the lessons that prevent a repeat. Each section contains a concrete timeline, a cost reference, and the specific mistakes that turn a manageable review into a protracted dispute. Three business scenarios – a manufacturing company, an IT firm with IP Box arrangements, and a foreign investor entering Poland – illustrate how the same rules play out differently in practice.

How does a KAS audit begin and what rights does the taxpayer have?

The audit opens with a written authorisation delivered to the taxpayer's registered address. That document names the auditing officer, defines the scope (a specific tax and period), and starts the procedural clock. From that moment, the taxpayer has 7 days to designate a representative and arrange access to premises. Ignoring this window is one of the most common early mistakes.

Polish tax law grants taxpayers a defined set of rights from day one. These include the right to be present during every inspection action, the right to submit explanations in writing, and the right to request copies of any document placed in the audit file. The Urząd Skarbowy (Tax Office) handling the case must register the audit in the Centralny Rejestr Podmiotów – Krajowa Ewidencja Podatników (Central Register of Taxpayers, CRP-KEP). Knowing these rights matters: officers sometimes move quickly, and a taxpayer who is not present may lose the chance to contest factual findings at source.

There is also a protection that many companies overlook. If the taxpayer belongs to a VAT group or uses KSeF Poland for structured invoice exchange, KAS can pull transactional data electronically before the first in-person visit. By the time the auditor arrives, the authority already holds a detailed picture of the company's invoice flows. Preparation must therefore begin before the letter arrives – not after.

  • Designate a tax advisor or legal counsel as the official representative within 7 days.
  • Secure all JPK (Standard Audit File) files for the audited period.
  • Identify the specific tax and period named in the authorisation.
  • Notify the board – personal liability questions arise early in complex audits.
  • Do not destroy, move, or alter any documents after receiving the authorisation.

For companies with cross-border structures, the opening phase carries additional weight. A German investor whose Polish subsidiary has intercompany loans may find that the audit scope expands to cover transfer pricing within the first two weeks. We secured a withdrawal of a preliminary transfer pricing adjustment exceeding PLN 3.5m for a manufacturing client in the Silesia region (autumn 2025) – precisely because the representative intervened at the authorisation stage and narrowed the defined scope before the documentation request was issued.

What documentation does KAS require and how should you respond?

The documentation phase is where most audits are won or lost. KAS will issue a formal request listing the records it needs. The taxpayer has a minimum of 3 days and a maximum of 14 days to respond, depending on the complexity of the request. Failure to deliver within the deadline – or delivering incomplete files – gives KAS grounds to estimate tax liability, which almost always produces a higher assessment than the actual position.

Standard documentation requests cover: VAT registers and JPK_VAT files, CIT calculations and supporting schedules, contracts with related parties (critical for transfer pricing reviews), and evidence of economic substance for any IP Box or R&D relief claimed. A tax advisor Warsaw-based practitioners know well: KAS officers increasingly cross-reference JPK data against KSeF Poland invoice records, spotting discrepancies that manual reviews would miss. Companies that adopted KSeF early often find this stage faster – their data is already structured.

Three scenarios illustrate the documentation challenge differently. A manufacturing company in Wielkopolska faces requests for physical goods-movement records alongside VAT invoices – missing delivery notes can void input-tax deductions. An IT firm claiming IP Box relief must produce a detailed nexus calculation showing that qualifying income is genuinely linked to owned intellectual property; a single missing R&D log can collapse the entire relief. A foreign investor with a Polish family foundation holding structure faces questions about whether the foundation's assets are correctly separated from the operating company's balance sheet.

(The family foundation rules, in force since May 2023, have become a regular audit focus – auditors are still testing the boundaries of what constitutes a legitimate foundation purpose versus a tax-avoidance arrangement.)

Respond to every documentation request in writing, even when the answer is that a document does not exist. Silence is treated as non-cooperation. Each written response creates a formal record that is essential if the case proceeds to appeal.

How are audit findings issued and what can you challenge?

Once KAS completes its review, it issues a post-audit report (protokół kontroli). The taxpayer has 14 days to file written objections. This is not a courtesy step – it is a substantive opportunity to contest factual errors, present additional evidence, and argue legal interpretation before any formal tax decision is issued. Missing this window effectively forfeits the strongest stage of the administrative process.

If KAS does not accept the objections, it issues a tax decision (decyzja podatkowa) specifying the additional liability, interest, and any penalty. Interest on underpaid tax accrues at the statutory rate – currently set by reference to the NBP (National Bank of Poland) reference rate plus a statutory multiplier – from the original payment deadline. On larger assessments, interest alone can exceed PLN 500,000 by the time a final decision is issued. That figure is not hypothetical; it is the reason early intervention matters.

The taxpayer may appeal to the Dyrektor Izby Administracji Skarbowej (Director of the Tax Administration Chamber) within 14 days of receiving the first-instance decision. If that appeal fails, the case moves to the Wojewódzki Sąd Administracyjny (Regional Administrative Court, WSA) and, ultimately, to the Naczelny Sąd Administracyjny (Supreme Administrative Court, NSA). The full administrative and judicial path can take 3 to 5 years. For companies with significant assessed liabilities, securing interim measures to protect cash flow during that period is often as important as the merits of the case itself.

We obtained a suspension of enforcement proceedings on an assessed liability of over PLN 4m for a logistics client in the Mazowieckie region (spring 2026), allowing the company to continue operations while the substantive appeal was heard. The legal basis for such suspension is narrow – but it exists, and it is worth pursuing in the right circumstances.

For directors, the personal liability dimension deserves separate attention. Under Polish corporate legislation, board members may be held jointly and severally liable for unpaid tax obligations of the company if the company cannot satisfy them. That exposure does not require any finding of fraud – it arises from the structural position of directorship itself. Details on director exposure are covered in our separate analysis of what Polish directors need to know about D&O insurance coverage.

What are the most common audit mistakes and how do you avoid them?

Most audit failures are procedural, not substantive. The underlying tax position is often defensible – but it becomes indefensible because of how the company responded during the audit. Four patterns repeat across industries and company sizes.

First: communicating verbally with auditors instead of in writing. Every conversation that is not documented can be characterised differently later. All substantive responses should be in writing, signed, and submitted through the official channel. Second: producing documents in batches without an index. KAS officers work under time pressure. An unindexed bundle of 800 pages will be read selectively – and the pages that are not read may be the ones that support your position.

Third: failing to engage a tax advisor before the first in-person meeting. Polish tax law is detailed and the procedural rules are strict. A company that sends its CFO to meet auditors without legal support is relying on goodwill rather than process. Fourth: underestimating transfer pricing exposure. Many companies with intercompany transactions have not updated their transfer pricing documentation since the relevant rules were tightened. KAS now requires benchmarking studies to be current within 3 years; outdated studies are treated as absent.

Companies using IP Box arrangements face a specific variant of this problem. The nexus calculation must be maintained in real time – it cannot be reconstructed retrospectively. An IT company in Małopolska that had been claiming IP Box relief for two years discovered during an audit that its development logs were insufficiently granular to satisfy the nexus requirement. The adjustment covered two full tax years. The exposure was avoidable with six months of proper record-keeping.

For businesses with any cross-border dimension – whether KSeF Poland invoice flows, intercompany financing, or a Polish family foundation holding structure – the complexity multiplies. Our guide on KSeF deadline and timeline considerations explains how structured invoice obligations interact with audit readiness. Companies operating across multiple jurisdictions may also find useful context in our analysis of what KSeF means for businesses in Slovakia, which addresses cross-border invoice-compliance questions that arise in KAS audits involving Slovak counterparties.

  • Keep a written log of every interaction with auditors, including dates and topics discussed.
  • Index all document submissions with a cover letter referencing the original request.
  • Review transfer pricing documentation currency before – not during – the audit.
  • Maintain IP Box nexus calculations on a rolling basis, not retrospectively.

The single most effective preparation step is a pre-audit internal review. Conducted by an independent tax advisor, it identifies the gaps that KAS will find – before KAS finds them. A voluntary correction filed before the audit notice arrives carries a significantly lower penalty rate than one filed under audit pressure. The difference can be 50% of the penalty amount.

Specific situations require tailored assessment. If your company holds intercompany positions, IP Box claims, or a Polish family foundation structure, the risk profile is not generic – it is particular to your facts and the current state of KAS enforcement priorities.

To receive an expert assessment of your audit exposure, contact info@kordeckipartners.com.

Frequently asked questions

Q: How long does a KAS tax audit typically last?

A: The standard audit period under Polish tax law is up to 12 months from the date the authorisation is served. Extensions are permitted in complex cases – particularly those involving transfer pricing or cross-border structures – and can push the active audit phase to 18 months or longer. The subsequent administrative appeal process is separate and adds further time. Companies should plan for the audit to affect internal resources for at least one full financial year.

Q: Is it a misconception that a clean VAT history protects against a CIT audit?

A: Yes – this is one of the most common misunderstandings. KAS conducts separate risk assessments for different taxes. A company with no VAT irregularities can still be selected for a CIT audit based on its IP Box claims, transfer pricing arrangements, or the profile of its related-party transactions. The selection algorithms are tax-specific. A clean VAT record provides no shield against a CIT or transfer pricing review.

Q: What are the likely costs of professional support during a KAS audit?

A: Costs depend heavily on the scope and complexity of the audit. A straightforward VAT audit of a single-entity business might be supported for a fixed fee in the range of PLN 15,000 to PLN 40,000. A multi-year CIT audit involving transfer pricing documentation and an administrative appeal can involve fees of PLN 100,000 or more, spread over 12 to 24 months. These figures are indicative. The relevant comparison is always the assessed liability that professional support is likely to reduce or eliminate.

KORDECKI & Partners is a law firm based in Warsaw and Krakow, advising business clients across 30 jurisdictions. Our team combines expertise in Polish and international law with a practical approach to tax advisory, KAS audit defence, and transfer pricing compliance. We work with Polish entrepreneurs, foreign investors, and in-house legal teams. To discuss your situation, contact info@kordeckipartners.com.

Disclaimer: This publication is provided for informational purposes only and does not constitute legal advice. The information herein should not be relied upon as a substitute for professional legal counsel tailored to your specific circumstances. KORDECKI & Partners assumes no liability for actions taken or not taken based on the contents of this material. For advice regarding your particular situation, please contact info@kordeckipartners.com.