Challenging a Tax Assessment Notice in Ukraine: Complaint or Court, and Which Deadlines Apply

A tax assessment notice is sent to a taxpayer when the tax authority itself determines the amount of a monetary liability – in particular, following an audit (paragraph 58.1 of the Tax Code of Ukraine). The notice states the amount and the basis of the charge (subparagraph 58.1.1). It can be challenged administratively or in court (paragraph 56.1). Below: the deadlines, how to file a complaint, what happens to payment while the dispute is pending, and how long you have to bring a claim.

How long you have to respond

The assessed amount must be paid within 10 working days following the day the notice is received, unless the taxpayer begins a challenge within that period (paragraph 57.3). A complaint to the higher-level tax authority is filed within the same 10 working days following the day the notice is received (paragraph 56.3). So it is worth settling on a position from the first day after the notice arrives.

Administrative challenge: how to file a complaint

• The complaint is filed with the higher-level tax authority in writing or electronically; complaints against decisions of territorial bodies of the State Tax Service are filed with the State Tax Service (paragraph 56.3).
• Where necessary, duly certified copies of documents, calculations and evidence that the taxpayer considers it necessary to provide are attached to the complaint (paragraph 56.3).
• In the complaint the taxpayer may state that it wishes to attend the hearing in person or through a representative, including by videoconference; the tax authority gives notice of the date, time and place (method) of the hearing at least five calendar days in advance (paragraph 56.3).
• In an administrative challenge, the burden of proving that the assessment is lawful lies with the tax authority (paragraph 56.4).

If the 10 working days have been missed, a complaint can be filed within six months after that period expires, together with an application to have the deadline reinstated and, where available, documents showing good reasons for the delay. The tax authority reinstates the deadline if it accepts the reasons as good (paragraph 56.3).

How long the complaint takes

The tax authority must take a reasoned decision and send it within 20 calendar days following the day the complaint is received (paragraph 56.8). The head of the authority may extend this period, but to no more than 60 calendar days, notifying the taxpayer before the 20-day period expires (paragraph 56.9).

If the decision is not sent within these periods – or the decision to extend is not sent before the 20 days expire – the complaint is deemed fully upheld in the taxpayer’s favour (paragraph 56.9). A decision of the State Tax Service on a complaint can no longer be challenged administratively, but it can be challenged in court (paragraph 56.10).

Do you have to pay while the dispute is pending?

• A complaint filed in time suspends performance of the monetary liabilities under the notice until the administrative challenge ends: no tax demands are sent, and the disputed amount is treated as not agreed (paragraph 56.15).
• If the taxpayer goes to court, the monetary liability is treated as not agreed until the day the court decision takes legal effect (paragraph 56.18).
• The day the administrative challenge ends is treated as the day the liability is agreed (paragraph 56.17); the agreed amount, penalty interest and fines must be paid within 10 working days after it is agreed (paragraph 57.3).

Going to court: which deadlines apply

A taxpayer can go to court without an administrative challenge. But a decision challenged in court can no longer be challenged administratively (paragraph 56.18). If a complaint was filed first, the claim is filed within one month following the day the administrative challenge procedure ends (paragraph 56.19).

On deadlines, the Grand Chamber of the Supreme Court reached the following conclusions in its judgment of 16 July 2025 in case No. 500/2276/24:

• the one-month period in paragraph 56.19 is special in relation to part 4 of Article 122 of the Code of Administrative Procedure and takes precedence in tax disputes (paragraphs 23, 24 and 28 of the judgment);
• paragraph 56.18 does not set a deadline for going to court; the 1,095 days in Article 102 of the Tax Code are a limitation period within which the right to challenge a notice is preserved, not a deadline for filing a claim (paragraph 27);
• the Grand Chamber departed from its own earlier wording, which was inconsistent with the conclusion of the Administrative Cassation Court in its judgment of 27 January 2022 in case No. 160/11673/20. Under that conclusion, without an administrative challenge the deadline for going to court is set by part 2 of Article 122 of the Code of Administrative Procedure – six months from the day the person learned or should have learned of the violation of their rights (paragraphs 26 and 27).

In that case the claim was filed almost two months after the one-month period had expired, and the courts refused to reinstate the deadline because no good reasons for missing it had been given (paragraphs 30–32 of the judgment).

Frequently asked questions

Can a complaint be filed after the 10 working days have passed?

Yes, within six months after the deadline expires, together with an application to reinstate it. The tax authority reinstates the deadline if it accepts the reasons for missing it as good (paragraph 56.3 of the Tax Code).

What happens if the tax authority does not respond to the complaint in time?

If a reasoned decision is not sent within 20 calendar days or the extended period (up to 60 days), the complaint is deemed fully upheld in the taxpayer’s favour from the day following the last day of the period (paragraph 56.9 of the Tax Code).

How long do I have to bring a claim after the State Tax Service rejects the complaint?

One month following the day the administrative challenge procedure ends (paragraph 56.19 of the Tax Code). The Grand Chamber of the Supreme Court confirmed that this is the period that takes precedence in tax disputes (judgment of the Grand Chamber of the Supreme Court of 16 July 2025 in case No. 500/2276/24).

Do the 1,095 days mean a claim can be filed within three years?

No. According to the Grand Chamber, the 1,095 days in Article 102 of the Tax Code are a limitation period, not a deadline for going to court (judgment of the Grand Chamber of the Supreme Court of 16 July 2025 in case No. 500/2276/24, paragraph 27). The deadline for going to court is set by paragraph 56.19 of the Tax Code (after a complaint) or part 2 of Article 122 of the Code of Administrative Procedure (without one).

This article reflects the position as of October 2026 (Tax Code as amended on 17 September 2026; judgment of the Grand Chamber of the Supreme Court of 16 July 2025 in case No. 500/2276/24). Tax legislation and case law change frequently; take advice before acting on it.

Received a tax assessment notice? A lawyer will assess the grounds for the charge and prepare a complaint within the 10-working-day deadline or a claim to court → Challenging tax assessment notices · Tax disputes in court