The issues related to the acquisition and loss of Polish citizenship are governed by the Polish Citizenship Act of April 2, 2009 (Journal of Laws of 2012, item 161).
The Act sets forth two basic principles concerning Polish citizenship. Stipulated in Article 2, the principle of continuity of Polish citizenship guarantees temporal continuity of the citizenship, from the moment of its acquisition, in accordance with the rules binding at that time, irrespective of subsequent amendments introduced to the legislation on citizenship. This means that the persons who acquired Polish citizenship pursuant to the previous rules, which were amended or revoked thereafter, who did not lose Polish citizenship, maintain it, in accordance with the rules in force upon the time of its acquisition. Simultaneously, this principle constitutes a guideline for competent authorities of the public administration on how to proceed in case of confirmation of Polish citizenship or its loss. The second principle, provided for in Article 3 of the Act – the principle of exclusivity of Polish citizenship – is directly related with the question of double (or multiple) citizenship, as it creates a clear conflict of guidelines in the case of its occurrence and allows for the elimination of its adverse effects. According to the draft of the Act, multiple citizenship is stipulated as admissible, on the condition that Polish citizenship takes absolute precedence. A Polish citizen may possess at the same time Polish citizenship and citizenship of another state, but even then, he or she maintains the same rights and duties towards the Republic of Poland as a person possessing only Polish citizenship, i. e. he or she may not effectively invoke before Polish authorities the simultaneously held foreign citizenship, or the rights or duties arising from it.