Taxpayers have the right to contribute to the evidentiary record

One of the fundamental principles of Polish tax proceedings is the obligation to establish the facts of the case thoroughly and accurately. The tax authority must take all necessary steps to determine the actual circumstances relevant to the outcome of the case.

This does not mean, however, that only the authority is responsible for building the evidentiary record. The principle of active participation allows taxpayers to submit their own evidence and request that specific evidentiary measures be carried out.

Evidence in tax proceedings may include documents, accounting records, witness testimony, expert opinions and any other means capable of helping to establish the facts. The catalogue of admissible evidence is open-ended, giving taxpayers broad opportunities to demonstrate circumstances relevant to their case.

When must the tax authority admit evidence?

The key provision is Article 188 of the Polish Tax Ordinance Act. Under this rule, a taxpayer’s request to admit evidence should be granted if it
concerns facts that are relevant to the case, unless those facts have already been sufficiently established by other evidence.

In other words, the tax authority may not arbitrarily disregard evidence submitted by a taxpayer. If the evidence could help clarify material facts, it should generally be admitted.

This principle was confirmed by the Supreme Administrative Court of Poland in its judgment of 11 December 2025 (case no. I FSK 1820/24). The Court held that a tax authority may not refuse evidence favourable to a taxpayer merely because it considers the existing evidentiary record sufficient. Such an approach could result in selective evidence gathering and undermine the principles of objectivity and impartiality.

This position is particularly important in practice. In tax disputes, authorities sometimes focus primarily on evidence supporting their own conclusions while downplaying evidence presented by taxpayers. Polish administrative courts have consistently emphasised that such an approach is incompatible with procedural rules.

The tax authority is not required to admit every piece of evidence

At the same time, a taxpayer’s right to submit evidentiary requests is not unlimited. Tax authorities are not obliged to admit every piece of evidence proposed by a party.

As the Supreme Administrative Court of Poland stated in its judgment of 11 April 2024 (case no. II FSK 1904/23), a refusal to admit evidence is justified not only where the relevant fact has already been sufficiently established by other evidence, but also where the fact in question is irrelevant to the outcome of the case or where the proposed evidence is incapable of proving that fact.

Similarly, in its judgment of 25 October 2023 (case no. I FSK 576/23), the Court stressed that Article 188 does not require authorities to grant every evidentiary request made by a taxpayer. A request may be refused where the relevant fact has already been established or where it is immaterial to the resolution of the case.

The Provincial Administrative Court in Poznań, Poland, reached a similar conclusion in its judgment of 21 March 2024 (case no. I SA/Po 874/23), holding that a taxpayer’s right to propose evidence does not automatically oblige the authority to carry out every requested evidentiary measure.

It should also be remembered that tax authorities are required to conduct proceedings efficiently and without undue delay. Consequently, requests that merely duplicate evidence already collected or cannot contribute to clarifying the facts of the case may be rejected. Admitting such evidence could unnecessarily prolong the proceedings.

From a taxpayer’s perspective, this means that evidentiary requests should be carefully prepared. Simply identifying a piece of evidence may not be sufficient. Taxpayers should explain which specific facts the evidence is intended to prove and why those facts are relevant to the outcome of the case.

What can a taxpayer do if evidence is refused?

A refusal to admit evidence is issued in the form of a procedural order. Importantly, under Polish tax procedure rules, such an order cannot be challenged by way of a separate interlocutory appeal.

This does not mean, however, that the authority’s decision is beyond review. The taxpayer may challenge the refusal in an appeal against the final tax decision.

If the matter subsequently reaches the administrative courts, the court will review the legality of the evidentiary proceedings and assess whether the authority had valid grounds for refusing the requested evidence.

It is worth noting that courts generally do not conduct evidentiary proceedings to the same extent as tax authorities. For this reason, submitting appropriate evidentiary requests during the audit or tax proceedings stage is often crucial to the effectiveness of a taxpayer’s defence.

Conclusion

The right to submit evidentiary requests is one of the key procedural safeguards available to taxpayers in disputes with Polish tax authorities. Although authorities are not required to admit every piece of evidence proposed by a taxpayer, any refusal must be based on specific legal grounds and properly justified. The practical takeaway is straightforward: taxpayers should actively participate in proceedings, submit evidence supporting their position, and ensure that their evidentiary requests are properly substantiated. In many cases, the outcome of a dispute with the tax authorities will depend largely on the evidentiary stage of the proceedings.