Did your ancestor lose Polish citizenship by becoming an American?

It depends above all on the year. Under the 1920 Citizenship Act, which applied until January 18, 1951, acquiring a foreign citizenship was a ground for losing Polish citizenship, and the loss also reached the wife and children under 18. People obliged to active military service were an exception. From January 19, 1951, a Polish citizen needed permission from the Polish authorities to take another citizenship, and the statutes tied the loss of Polish citizenship to that permission.

Why does the date of naturalization decide so much?

Citizenship by descent passes at birth, and only from a parent who is a Polish citizen at that moment. Today Article 14 of the 2009 Act says that a child acquires Polish citizenship by birth where at least one parent is a Polish citizen. The 1920 Act was narrower: a child born to married parents took the father's citizenship, and a child born outside marriage took the mother's (Article 5).

For every generation the question is therefore the same: was the parent still a Polish citizen on the day the child was born? The answer comes from the statute in force at the time of each event:

• January 31, 1920 to January 18, 1951: the Act of January 20, 1920 on Citizenship of the Polish State,
• January 19, 1951 to August 20, 1962: the Act of January 8, 1951 on Polish Citizenship,
• August 21, 1962 to August 14, 2012: the Act of February 15, 1962 on Polish Citizenship,
• since August 15, 2012: the Act of April 2, 2009 on Polish Citizenship.

What did the 1920 Act say about naturalization?

Article 11 listed two grounds for losing Polish citizenship: acquiring a foreign citizenship, and taking public office or joining the army of another country without the Polish government's consent. Article 13 extended the loss to the wife and to children under 18, unless the decision provided otherwise.

Two things follow for descendants. The extension did not reach a child who was already older than 18 when the father naturalized. And a child born in the United States after the father's naturalization could not acquire Polish citizenship from him, because on that day he was no longer a Polish citizen.

Women need a separate look. The 1920 Act itself refers to Polish women who lost citizenship by marrying a foreigner (Article 10). The rule changed on January 19, 1951, when marriage to a foreigner stopped affecting either spouse's citizenship (Article 5 of the 1951 Act).

One more prewar rule can break the chain. A 1938 statute allowed the authorities to deprive a citizen living abroad of Polish citizenship by an individual decision, for example after at least five years abroad without ties to the Polish state.

Was there an exception connected with military service?

Yes. The second paragraph of Article 11 provided that people obliged to active military service could acquire a foreign citizenship only with permission, originally from the Minister of Military Affairs. Without it, the Polish state did not stop regarding them as Polish citizens. From December 25, 1932, the condition became release from the general military obligation.

This is why an ancestor's military history matters. When a wojewoda (voivode, the central government's representative in a Polish province, who decides on confirmation of citizenship) examines a naturalization from before January 19, 1951, the documents requested include proof of the naturalization and a document showing whether the person served in a foreign army. Serving in a foreign army without consent was itself a separate ground for loss.

What changed on January 19, 1951?

The 1951 Act reversed the starting point. Under Article 11, a Polish citizen could acquire a foreign citizenship only after obtaining permission to change citizenship, and it was an acquisition made under those rules that led to loss. The 1962 Act kept the requirement (Article 13), and in both Acts permission granted to parents extended to children under their parental authority.

In practice, a voivode asked to confirm that citizenship was lost after 1951 requests a copy of the permission decision, or a statement of when and by which authority it was issued. Since August 15, 2012, a Polish citizen loses citizenship only by renouncing it with the consent of the President of Poland.

What if citizenship was in fact lost?

A person who lost Polish citizenship before January 1, 1999 under Article 11 or 13 of the 1920 Act, Article 11 or 12 of the 1951 Act, or Article 13, 14 or 15 of the 1962 Act may apply for restoration (Article 38 of the 2009 Act). The Minister of the Interior and Administration decides, and from the United States the application is filed through a consul for a fee of $59. According to the ministry, children cannot be included in the application, so the position of descendants born after the loss has to be examined separately.

Which documents answer the question?

• a document showing the date of the ancestor's U.S. naturalization,
• Polish documents from before emigration that show the ancestor's citizenship, such as a passport or a military record,
• any record of service in a foreign army, including the U.S. armed forces,
• birth and marriage records for each generation, so that each birth can be placed before or after the naturalization.

The application for confirmation must include details of the applicant's parents and grandparents (Article 56 of the 2009 Act). How the confirmation itself works, and what it costs, is explained in our guide on confirming Polish citizenship.

How we help

We build a timeline for each generation, match every naturalization and birth to the statute in force at the time, search for the military and civil records that decide the exception, and file the application under a power of attorney. When the documents show that the chain was broken, we tell you so plainly and explain whether any other route is open.

This article is general information about Polish law, not legal advice about your family's situation, and it does not describe U.S. nationality law. Legal basis: the Act of January 20, 1920 on Citizenship of the Polish State (Journal of Laws 1920 No 7 item 44), Articles 5, 10, 11 and 13, as amended by the Regulation of the President of December 3, 1932 (Journal of Laws 1932 No 109 item 896); the Act of March 31, 1938 on Deprivation of Citizenship (Journal of Laws 1938 No 22 item 191), Article 1; the Act of January 8, 1951 on Polish Citizenship (Journal of Laws 1951 No 4 item 25), Articles 5, 11 and 12; the Act of February 15, 1962 on Polish Citizenship (Journal of Laws 1962 No 10 item 49), Articles 13 and 15; the Act of April 2, 2009 on Polish Citizenship (consolidated text, Journal of Laws 2025 item 1611), Articles 14, 38, 46 and 56; together with guidance from the Małopolska Voivode's Office, the Ministry of the Interior and Administration, and the Polish consular service in the United States. If you would like to know how this applies to your family, describe your situation.