You work in Poland but have income or residence abroad? We explain how double taxation treaties protect you from paying tax twice — and what role the certificate of residence plays.
1. Where double taxation comes from
When income may be taxed in two countries (e.g. in the country of work and in the country of residence), a risk of double taxation arises. It is resolved by double taxation treaties (DTTs), usually based on the OECD Model Convention.
2. Methods of avoiding double taxation
| Method | What it involves |
|---|---|
| Exemption with progression | Foreign income is exempt in Poland but affects the rate applied to Polish income |
| Proportional deduction | Foreign income is taxed in Poland, with a deduction of the tax paid abroad |
Which method applies in a given case follows from the particular DTT. Under the proportional deduction method, the abolition relief (Article 27g of the PIT Act) may be available, within the statutory limit.
3. Certificate of residence
To apply a DTT (e.g. a lower withholding rate), a certificate of residence is usually required — an official confirmation of the place of residence issued by the administration of the other country.
4. Example: Poland–Ukraine
A separate double taxation treaty is in force between Poland and Ukraine. For income of Ukrainian citizens working in Poland it is worth establishing residence and applying the method that follows from that treaty.
Show more: how tie-breaker rules work in cases of dual residence
Tie-breaker rules
When two countries treat a person as a resident, the DTT applies criteria in sequence: permanent home → centre of vital interests → habitual abode → nationality → agreement between the authorities. Establishing the correct residence is the starting point for a correct settlement.
Do you have income in two countries? We will settle it without double taxation
We will determine the applicable treaty and method, help obtain a certificate of residence and correctly apply the abolition relief, if it is available.
Book a free consultationLegal notice: this article is for information purposes only and does not constitute legal or tax advice. Legal status: 2026 (Act of 26 July 1991 on PIT, including Article 27g; the relevant double taxation treaties based on the OECD Model Convention).
Sources: the PIT Act, including Article 27g; the relevant double taxation treaties; podatki.gov.pl — list of DTTs. The above commentary is our own; the provisions cited should be verified against the current text of the act before taking any action.