Citizenship by descent is the acquisition of citizenship through ancestral lineage rather than birth in a country's territory or through formal naturalization. An applicant qualifies for citizenship by descent if one or more ancestors—typically parents, grandparents, or in some cases more distant forebears—held citizenship of a country at a relevant time. This pathway is based on the legal principle of jus sanguinis ("right of blood"), which determines citizenship through parentage rather than birthplace.
Citizenship by descent operates under jus sanguinis, the principle that citizenship passes through family lineage. This contrasts with jus soli ("right of the soil"), which grants citizenship based on birthplace in a country's territory. Most European, Asian, and Middle Eastern countries apply jus sanguinis, while most countries in the Americas (including the United States, Canada, Brazil, and Mexico) apply jus soli. Some countries apply both simultaneously—France grants citizenship to those born in France to at least one French-born parent (jus sanguinis) and to those born in France to foreign parents who were themselves born in France (modified jus soli), creating overlapping eligibility.
The practical consequence of jus sanguinis is that descendants of immigrants maintain eligibility for their ancestral country's citizenship, sometimes indefinitely across multiple generations. An American descended from Italian immigrants can acquire Italian citizenship despite having no personal connection to Italy and being born and raised in the United States. This principle has facilitated what is sometimes called "ancestral citizenship" or "diaspora citizenship"—the acquisition of citizenship by individuals living outside a country but descended from its former citizens.
Ireland exemplifies a generous descent policy through its Foreign Births Registry. Irish citizens can register descendants born abroad, and any person with at least one grandparent who was an Irish citizen (with certain conditions) can claim Irish citizenship, even if neither parent was Irish and the applicant was born outside Ireland. However, a recent 2024 policy change will restrict this to applicants with at least one parent who is an Irish citizen, eliminating the grandparent rule for new applicants. This change reflects evolving policy toward more restrictive descent provisions.
Italy maintains one of the world's most generous jus sanguinis provisions, permitting descent-based citizenship without generational limits. An Italian can pass citizenship to descendants indefinitely, provided that the citizenship line was never broken by an ancestor naturalizing in another country before the next generation's birth. This "1948 rule" states that the ancestry chain must be unbroken through a critical date (January 1, 1948), after which the chain can continue indefinitely. An American descended from a great-grandparent who emigrated from Italy before becoming a US citizen may be ineligible if that ancestor naturalized before 1948, but applicants with unbroken Italian ancestry lines have successfully claimed Italian citizenship across multiple generations.
Poland permits descent-based citizenship for descendants of Polish citizens who lost Polish citizenship through emigration or other means. Documentation requirements are stringent, requiring vital records, naturalization records, and genealogical evidence tracing unbroken ancestry. Processing can take 2 to 5 years given documentation requirements.
Germany permits descent-based citizenship for children of German citizens born abroad. Additionally, through the "Option Model" (Optionsmodell), children born in Germany to non-citizen parents can acquire German citizenship if they can demonstrate descent from a German citizen through an ancestor who lost citizenship as a result of Nazi persecution or post-1949 expulsion. This provision, created to remedy historical injustices, permits acquisition of German citizenship by descendants of individuals who fled persecution.
Hungary permits descent-based citizenship for ethnic Hungarians (defined through ancestral nationality rather than ethnicity, despite sometimes being referred to in ethnic terms). Applicants must demonstrate Hungarian ancestry and may pursue citizenship through a streamlined process.
Portugal, prior to 2022, maintained a generous provision permitting descendants of Sephardic Jews expelled from Portugal in the 1490s to claim citizenship. This unique historical provision permitted thousands of descendants of Sephardic Jewish diaspora communities to acquire Portuguese citizenship. The program was terminated in 2022, though earlier applicants retain citizenship acquired under this provision.
The United Kingdom permits descent-based citizenship in limited circumstances. Children of British citizens born abroad automatically acquire British citizenship at birth. Additionally, British Overseas Citizens (a category created for citizens of former colonies) and British Protected Persons may have eligibility for UK citizenship depending on their circumstances.
Citizenship by descent applications require extensive historical documentation establishing an unbroken ancestral chain through vital records. Required documents typically include birth certificates for the applicant and all ancestors in the chain, marriage certificates documenting family relationships, death certificates for deceased ancestors, naturalization or immigration records for ancestors who emigrated, and divorce decrees if applicable. Additionally, all documents must be "apostilled" (authenticated through a special international process) and often translated into the destination country's official language.
Vital records pose significant challenges. Older records may not exist, may be lost or destroyed (particularly for families from regions experiencing wars or revolutions), or may be difficult to access in countries with poor record-keeping infrastructure. Birth certificates from certain countries or time periods may not have been formally issued, making proof of birth legally difficult.
Naturalization records are particularly critical for maintaining unbroken citizenship chains under jus sanguinis. An ancestor who naturalized in another country effectively broke the citizenship chain at that point. For Italy's jus sanguinis, an ancestor naturalizing before 1948 severs the line; for Ireland's previous system, an ancestor naturalizing anywhere breaks the line. Tracing naturalization records requires accessing historical immigration and naturalization records from multiple countries.
Professional genealogy services specializing in citizenship research are increasingly common, and many applicants engage these services to locate and authenticate documentation. Genealogists can access historical records archives, interpret documents in various languages, and guide applicants through the documentation process. Professional genealogy services typically cost $2,000 to $10,000 depending on complexity and how far back the ancestry must be traced.
Citizenship by descent applications, when documentation is complete, typically process within 6 to 18 months, though extended timelines are common due to documentation challenges. Applications missing critical documents are often rejected or suspended pending document provision, potentially extending timelines by years.
Costs for citizenship by descent are substantially lower than citizenship by investment programs. Government fees typically range from $500 to $3,000. Professional legal fees for managing applications range from $1,500 to $5,000. Genealogy research and documentation acquisition may cost $2,000 to $10,000 depending on complexity. A comprehensive citizenship by descent acquisition, if documentation is accessible, typically costs $5,000 to $15,000 total, substantially less than the six-figure costs of most citizenship by investment programs.
A key distinction exists between automatic citizenship acquisition and registration-based systems. In some countries, citizenship by descent is automatically acquired at birth if the applicant's parent is a citizen of the descent country, regardless of where the child is born. In others, citizenship is not automatically acquired but must be formally registered, and the registration process can occur at any time during the applicant's life (even decades after birth).
Italy's system operates through both mechanisms depending on the applicant's circumstances. Children born abroad to Italian citizen parents born after 1948 automatically acquire Italian citizenship at birth (unless the Italy parent lost citizenship through naturalization elsewhere). Applicants whose lines are broken before 1948 can still claim citizenship through judicial proceedings. Ireland's previous system (now being reformed) operated entirely through registration—applicants did not automatically acquire citizenship but could register for it at any age if they met descent requirements.
This distinction matters practically because applicants with automatic acquisition may not need to take affirmative steps to acquire citizenship, while those with registration-based systems must actively apply. Additionally, applications submitted during a person's lifetime operate differently from applications submitted after death—some countries permit descendants to claim based on deceased ancestors while others require the ancestor to have been alive to hold citizenship.
Several categories of applicants face particular difficulty in obtaining citizenship by descent. Those from countries experiencing wars, revolutions, or significant governmental disruptions (such as Ottoman-era Eastern Europe, post-Soviet states, or Middle East) often cannot locate or access historical records. Those whose ancestors changed family names (whether by formal legal change, anglicization, or informal adoption) face challenges matching surnames across documents and generations.
Applicants with ancestors from regions that have changed borders (Eastern Europe, the Balkans, parts of Asia) must navigate the historical record to determine which country's citizenship their ancestor held—the relevant country may no longer exist with that name, have broken apart, or have been incorporated into other nations. For example, ancestors from the Austro-Hungarian Empire could have been citizens of multiple successor states.
Illegitimacy, adoption, or other non-traditional family structures complicate applications. Some countries' historical citizenship laws made citizenship transmission through only certain family relationships (for example, only through biological parents, not adoptive parents; only through marriage, not out-of-wedlock birth). Understanding the historical laws governing the relevant country and time period becomes critical.
Citizenship by descent offers a fundamentally different pathway compared to citizenship by investment or residency by investment. Descent-based acquisition requires no investment, no residency in the target country, and no ongoing obligations—it is purely based on family history. This makes descent-based citizenship attractive for applicants fortunate enough to be eligible, as the barriers are primarily documentation challenges rather than financial or time investment.
For applicants ineligible for descent-based citizenship, citizenship by investment or residency followed by naturalization are alternative pathways. The strategic approach for many applicants is to explore descent eligibility first (given the minimal cost), and if ineligible, pursue more expensive investment-based pathways.