A Warsaw-based technology company is locked in a contractual dispute with a Polish subcontractor. The core question – whether the delivered software met the agreed specification – turns entirely on technical assessment. Neither the judge nor the opposing counsel has the expertise to resolve it. The outcome of the case depends on a single procedural instrument: the court-appointed expert witness.

In Polish civil proceedings, a court-appointed expert witness (biegły sądowy) provides a written opinion that the court uses to resolve factual questions requiring specialist knowledge. The expert is nominated from a register maintained by each Regional Court (Sąd Okręgowy), and the appointment is ordered by the presiding judge. Parties may challenge the expert's impartiality or the content of the opinion, but they cannot simply substitute their own specialist report for the court-appointed one.

This guide walks through the full procedure step by step: how experts are appointed, how to contest an unfavourable opinion, what the process costs, and where foreign investors typically lose ground. Three business scenarios – a manufacturing dispute, an IT contract claim, and a foreign investor's construction case – illustrate the practical stakes at each stage.

How does the court appoint an expert witness in Poland?

The appointment process begins when the judge identifies a factual issue that cannot be resolved without specialist knowledge. Either party may apply for an expert, or the court may act on its own motion. The judge then selects a biegły sądowy from the register held by the Regional Court (Sąd Okręgowy) in the relevant jurisdiction. Registration is supervised by the court president, and experts are listed by discipline – accounting, construction, IT, medicine, and many others.

Once appointed, the expert receives a formal set of questions (teza dowodowa) from the court. These questions define the exact scope of the opinion. The expert cannot go beyond them without the court's permission. This is a critical point for litigants: if the questions are framed too narrowly, the resulting opinion may miss the most commercially significant issues entirely. Parties should submit written proposals for the expert's questions before the appointment order is issued – that window closes quickly.

The expert then has a court-set deadline to deliver the written opinion, typically 30 to 90 days depending on complexity. In practice, extensions are common. The National Court Register (KRS) records used in accounting disputes often require cross-referencing with multi-year financial data, and delays of six months or more are not unusual in complex commercial cases. We secured a favourable framing of expert questions in a construction dispute for a German investor's subsidiary in Lower Silesia (autumn 2025), which later proved decisive when the expert's opinion fully addressed the defect liability timeline.

  • Submit proposed expert questions in writing before the appointment hearing.
  • Check the expert's registration status and declared specialisation on the Regional Court list.
  • Verify whether the expert has any prior connection to the opposing party.
  • Request that the court specify a firm deadline in the appointment order.
  • Prepare documentary evidence the expert will need before the opinion is commissioned.

What are the costs and timelines involved?

Expert witness costs in Polish proceedings are governed by regulations setting tariff rates for different disciplines. The court fixes an advance payment (zaliczka), typically between PLN 2,000 and PLN 15,000, which must be deposited by the requesting party within a court-set deadline – usually 14 days. Failure to pay the advance can result in the motion being dismissed. Final remuneration is determined after the opinion is submitted and may exceed the advance significantly in complex technical cases.

Costs are ultimately allocated in the final judgment. The losing party generally bears the full cost of expert opinions ordered during the proceedings. In cases where both parties share partial success, the court apportions costs proportionally. Foreign investors sometimes underestimate this exposure: in a multi-expert commercial dispute, expert costs alone can reach PLN 80,000 to PLN 150,000 before accounting for legal fees.

Timeline is equally significant. From the appointment order to delivery of the written opinion, the realistic range is three to nine months. If the court then schedules a hearing for the expert to give oral clarification (wyjaśnienia ustne), add another two to four months. In total, a dispute requiring expert evidence in a first-instance court in Warsaw can take 18 to 36 months from filing to judgment. Parties who treat the expert phase as a formality – rather than a strategic opportunity – often find that the case is effectively decided before they realise it.

For a dispute lawyer advising a manufacturing client in the Mazowieckie region (spring 2026), we structured the evidentiary phase so that the expert's questions were aligned with the contractual defect clauses from the outset. This reduced the need for supplementary opinions and cut the expert phase by approximately four months.

How can parties challenge an expert opinion?

An unfavourable expert opinion is not the end of the road. Polish procedural law provides several mechanisms to contest it. The first is a written objection (zastrzeżenia do opinii) submitted to the court, identifying specific errors, gaps, or methodological flaws in the expert's reasoning. The court then decides whether to ask the same expert for supplementary clarification or to appoint a new expert entirely.

The second mechanism is a request for a second expert opinion from a different specialist. Courts grant this sparingly – the threshold is genuine doubt about the reliability of the first opinion, not mere dissatisfaction with its conclusions. Submitting a private expert report alongside the objection significantly strengthens the argument for a second appointment. Note, however, that a private report does not carry the same evidentiary weight as a court-appointed opinion. It functions as a tool of persuasion, not proof.

The third option is to challenge the expert's impartiality before or shortly after appointment. Grounds include a prior professional relationship with the opposing party, a financial interest in the outcome, or prior involvement in the subject matter. The challenge must be filed promptly – delay forfeits the right. Personal liability for procedural costs may arise if a challenge is filed frivolously. This dynamic is relevant not only in standard civil litigation but also in Krajowa Izba Odwoławcza (National Appeals Chamber, KIO) appeal proceedings, where expert evidence occasionally features in procurement disputes.

For foreign companies engaged in arbitration Poland proceedings, it is worth noting that the rules differ. Arbitral tribunals are not bound by the court-expert register and may appoint any qualified specialist. The evidentiary framework is more flexible, which can work to a well-prepared party's advantage.

What mistakes do foreign investors most often make?

The single most common error is treating the expert appointment as a passive event. Parties assume the court will ask the right questions and the expert will find the relevant facts. In reality, the scope of the opinion is shaped by whoever engages most actively at the pre-appointment stage. A dispute lawyer who submits detailed, precisely worded proposed questions before the hearing controls the evidentiary agenda. One who waits for the order to be issued has already lost that opportunity – and the loss is largely irreversible.

The second mistake is underestimating the expert's deadline. Courts set deadlines, but enforcement is weak. An expert who misses the deadline faces no automatic sanction unless the party applies for a penalty (grzywna) under civil procedure rules. Few parties do. The result is that proceedings stall for months while the expert works through a backlog. Proactive follow-up through counsel – including formal applications to the court if delays become excessive – keeps the case moving.

Three business scenarios illustrate the pattern. A manufacturing company in Silesia failed to propose expert questions and received an opinion that addressed quality standards but ignored the contractual delivery schedule – the commercially critical issue. An IT firm in Warsaw submitted a private technical report without filing formal objections, and the court declined to order a second opinion. A foreign investor in a construction dispute near Kraków challenged the expert's impartiality two months after appointment; the court dismissed the challenge as time-barred.

Sanctions compliance considerations occasionally intersect with expert evidence in cross-border disputes. Where a party's conduct is alleged to have violated trade restrictions, a financial or regulatory expert may be appointed to assess the economic substance of transactions. In those cases, the framing of expert questions becomes even more sensitive. For context on how foreign companies manage Polish dispute risk more broadly, see our analysis of dispute resolution for Spain companies doing business in Poland and dispute resolution for Cyprus companies doing business in Poland.

What should you prepare before expert proceedings begin?

Preparation before the expert phase opens is the single greatest lever available to litigants. Courts move quickly once the appointment order is issued. Parties who arrive at the pre-appointment hearing without a documented position on expert questions, proposed specialist disciplines, or advance payment capacity are immediately disadvantaged.

The checklist below covers the minimum preparation for any case where expert evidence is likely. It applies equally to litigation in Warsaw, arbitration Poland proceedings, and KIO appeal disputes in public procurement.

  • Identify the specific factual questions the expert must answer – in writing, before the first hearing.
  • Research registered experts in the relevant discipline at the competent Regional Court.
  • Budget for the advance payment deposit: allow PLN 15,000 as a baseline for complex commercial cases.
  • Prepare a documentary file for the expert: contracts, correspondence, technical specifications, and financial records.

Companies undergoing liquidation should note that expert evidence can arise in asset valuation disputes during winding-up. For an overview of how liquidation intersects with pending proceedings, see our guide on liquidation of sp. z o.o. – process and timeline.

The Polish Financial Supervision Authority (KNF) may also commission independent expert assessments in regulatory proceedings. If your company faces a KNF inquiry alongside civil litigation on the same facts, the expert opinions produced in each forum can influence the other. Coordinating the evidentiary strategy across both tracks requires early attention – waiting until opinions are finalised precludes any meaningful adjustment.

A specific figure worth anchoring: if the expert's written opinion is challenged and a supplementary opinion is ordered, the total expert-related costs in a mid-complexity commercial dispute in Warsaw typically reach PLN 30,000 to PLN 50,000. Plan for this before the first hearing, not after the first opinion arrives.

If your company is entering or defending proceedings where expert evidence will be determinative, the preparation phase is where the outcome is shaped. To receive an expert assessment of your evidentiary strategy, contact info@kordeckipartners.com.

Frequently asked questions

Q: Can a party in Polish proceedings use its own private expert instead of a court-appointed one?

A: A party may submit a private expert report as documentary evidence, but it does not carry the same weight as a court-appointed opinion. The court is not bound by a private report and will typically treat it as a party's submission rather than independent evidence. To challenge a court opinion effectively, a private report must be accompanied by formal written objections identifying specific methodological errors in the court-appointed opinion. The court then decides whether those objections justify ordering a supplementary or second opinion.

Q: How long does the expert phase typically add to a Polish court case?

A: From the appointment order to delivery of the written opinion, expect three to nine months. If oral clarification is scheduled, add another two to four months. In complex commercial disputes – particularly those involving accounting, construction, or IT – delays beyond this range are common. Parties should factor the expert phase into their overall litigation budget and timeline from the outset, as extensions are difficult to prevent once the expert has been appointed.

Q: Is it true that the court always follows the expert's opinion?

A: This is a common misconception. The court is not legally bound by the expert's opinion and may depart from it if the reasoning is internally inconsistent, the expert exceeded the scope of the questions, or the opinion conflicts with other evidence on record. In practice, courts do follow expert opinions in the majority of cases – but a well-constructed written objection that identifies genuine flaws can lead the court to discount or disregard the opinion entirely. The quality of the objection matters as much as the quality of the opinion itself.

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 commercial litigation and dispute resolution. We work with Polish entrepreneurs, foreign investors, and in-house legal teams navigating complex evidentiary proceedings. 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.