( or , ), meaning 'right of blood', is a principle of nationality law by which nationality is determined or acquired by the nationality of one or both parents. Children at birth may be nationals of a particular state if either or both of their parents have nationality of that state. It may also apply to national identities of ethnic, cultural, or other origins. Citizenship can also apply to children whose parents belong to a diaspora and were not themselves citizens of the state conferring citizenship. This principle contrasts with jus soli ('right of soil'), which is solely based on the place of birth.
In the 21st century, almost all states apply some combination of jus soli and jus sanguinis in their nationality laws to varying degrees, in contrast to largely pure forms of either as used in the 19th and 20th centuries. Historically, the most common application of jus sanguinis is a right of a child to their father's nationality. The majority of countries have since extended this right on an equal basis to the mother. Some apply this right irrespective of the place of birth, while others may limit it to those born in the state. Some countries provide that a child acquires the nationality of the mother if the father is unknown or stateless, and some irrespective of the place of birth. Some such children may acquire the nationality automatically while others may need to apply for a parent's nationality.
Most countries with mixed systems extend jus soli citizenship on a limited basis only to children born in their sovereign territory who do not qualify for citizenship elsewhere to avoid statelessness—an obligation for states party to the Convention on the Reduction of Statelessness. When the sovereignty over a territory is transferred from one state to another, individuals may be given the right of option of nationality based on jus sanguinis, typically on the condition of emigration from the ceded territory, or other rules.
Modern development Originally, the term nation was synonymous with ethnicity. However, at the end of the 19th century, the French-German debate on nationality saw the French, such as Ernest Renan, oppose the German conception, exemplified by Johann Fichte, who believed in an 'objective nationality', based on blood, race, or language. Renan's republican conception (with perhaps the presence of a German-speaking population in Alsace-Lorraine) explain France's early adoption of jus soli.
Mixed standards Many nations have a mixture of jus sanguinis and jus soli. For example, the United States grants citizenship based on jus soli to almost all people born within its borders, and also grants citizenship based on jus sanguinis to children born outside its borders to U.S. citizen parents subject to the parents meeting certain residency or physical presence criteria. The United Kingdom usually applies jus sanguinis, but also has a jus soli principle for children of foreign citizens living in the U.K. depending on the parents' nationality and legal residence status. About 60% of all countries worldwide have a limited jus soli principle that extends citizenship to children born within their borders who do not qualify for citizenship in any other country. Countries which ratified the Convention on the Reduction of Statelessness are obligated to enact laws as a solution for statelessness.
Complications due to imposed boundaries Some modern European states which arose out of the dissolved Austro-Hungarian or Ottoman empires have huge numbers of ethnic populations outside of their new national boundaries, as do most of the former Soviet states. Such long-standing diasporas do not conform to codified 20th-century European rules of citizenship. In many cases, jus sanguinis rights are mandated by international treaty, with citizenship definition imposed by the national and international community. In other cases, minorities are subject to legal and extra-legal persecution and choose to immigrate to their ancestral home country. States offering jus sanguinis rights to ethnic citizens and their descendants include Italy, Greece, Turkey, Bulgaria, Lebanon, Armenia, Hungary and Romania.
Jus sanguinis states
Africa StateLawAccording to Article 6 of the Algerian nationality law, a person is born Algerian if the person has either an Algerian father or mother.According to the nationality law of the Arab Republic of Egypt and its latest amendments, children born to an Egyptian father or an Egyptian mother acquire citizenship at birth, regardless of their place of birth.According to the Libyan nationality law, a person is born Libyan if the person has an Libyan father, but for a Libyan mother can only pass her nationality to her children under very limited and specific circumstances.Moroccan nationality law works according to Article 6, which says a child born of a Moroccan father or a Moroccan mother is a Moroccan by filiation.According to Article 14(1) of the Constitution of Kenya, 2010 a person becomes a citizen by birth if on the day of the person's birth either parent is a citizen of KenyaNigerian nationality law works in accordance to chapter 3, section 25 1C of the Nigerian Constitution, which states any person who has at least one Nigerian parent is eligible for citizenship.According to the Tunisian nationality law, when one of the parents is Tunisian, a child is considered Tunisian regardless of the child's place of birth or whether the child has acquired the nationality of another country. According to Section 2 of the South African nationality law, a child born to at least one South African citizen is considered South African, no matter where the child was born.
North America StateLawUnder Canadian nationality law, citizenship by descent is generally available to any person born to a Canadian citizen parent. Between 2009 and 2025, the "first-generation limit" restricted citizenship to only those born abroad within one generation of a native-born or naturalized citizen parent.
On December 15, 2025, Bill C-3 (An Act to amend the Citizenship Act (2025)) came into effect, repealing the first-generation limit and establishing a new framework based on the date of birth: Born before December 15, 2025: Anyone previously excluded by the first-generation limit automatically became a Canadian citizen on this date. This restoration is retroactive to birth and does not require the parent to meet any residency or "substantial connection" requirements. Born on or after December 15, 2025: For children born abroad beyond the first generation, a "substantial connection" test applies. A Canadian parent born abroad can only pass citizenship to their child if the parent was physically present in Canada for a cumulative total of at least 1,095 days (three years) prior to the child's birth or adoption.
This change was introduced following the 2023 Ontario Superior Court ruling in Bjorkquist et al. v. Attorney General of Canada, which found the previous limit unconstitutional for creating "lesser classes" of citizenship.According to the Dominican constitution, a child born abroad to at least one Dominican parent is a citizen.According to Haitian nationality law, every child born to a Haitian father or mother, no matter where he or she was born, is Haitian by the Haitian Constitution. This has been a big issue in the current Dominican nationality law; because of this and other factors, undocumented migrants' children born in the DR of Haitian origin are considered non-Dominicans, and therefore Haitians.Article 30 of the Mexican Constitution states that persons born abroad to at least one Mexican parent are Mexicans by birth.U.S. nationality law states that a child born abroad is given United States citizenship at birth if at least one parent is a citizen or a national, subject to certain conditions.
South America StateLawArgentine nationality lawArticle 12, paragraph I b and c of the Constitution of Brazil establishes that a child born outside of Brazil to at least one Brazilian parent is a Brazilian national pending registration at the consular office or subsequent registration if residing in Brazil. They are considered originary Brazilian nationals as they are attributed Brazilian nationality by birth. Chilean nationality lawColombian nationality lawSurinamese nationality lawArticles 32 to 42 of the Constitution of Venezuela.
Asia StateLawThe Armenian nationality law is mentioned by Article 47 of the Armenian constitution. It states that every child whose one parent is a citizen of the Republic of Armenia shall have the right to acquire citizenship of the Republic of Armenia.The Azerbaijani nationality law is mentioned by Article 52 of the Azerbaijani constitution. It states that a person whose one parent is a citizen of the Republic of Azerbaijan is a citizen of the Republic of Azerbaijan.Under Article 4 of Cambodia's law on nationality any child who is born from a mother or father who has Khmer nationality obtains Khmer nationality by birth, regardless of the place they were born.According to Article 5 of the Chinese nationality law, any person born abroad with a parent who is a Chinese national shall have Chinese nationality. But a person who has acquired a foreign nationality at birth and whose parents have acquired permanent residency abroad or foreign citizenship shall not have Chinese nationality.Indian nationality law. A child born in India on or after 3 December 2004 is considered a citizen of India by birth if both the parents are citizens of India or one of the parents is a citizen of India and the other is not an illegal migrant at the time of his birth. A person born outside India is considered as a citizen of India if either of his parents was a citizen of India by birth at the time of his birth, the parents must declare that the minor does not hold a passport of another country and have the birth registered at an Indian consulate within one year of the date of birth or with the permission of the Central Government, after the expiry of this period.The Indonesian nationality law states that persons born anywhere to one Indonesian parent are Indonesian by birth.According to the Iranian nationality law the following people are considered to be Iranian nationals:
All people residing in Iran except those whose foreign nationality is established; the foreign nationality of such people is considered to be established if their documents of nationality have not been objected to by the Iranian Government. Those born in Iran or outside whose fathers are Iranian. Those born in Iran of unknown parentage. People born in Iran of foreign parents, one of whom was also born in Iran. People born in Iran of a father of foreign nationality who have resided at least one more year in Iran immediately after reaching the full age of 18; in other cases their naturalization as Iranian subjects will be subject to the stipulations for Iranian naturalization laid down by the law. Every woman of foreign nationality who marries an Iranian husband. Every foreign national who has obtained Iranian nationality.