Bulgarian citizenship is regulated by the Constitution and the Citizenship law of 1998 as amended in 2009. Citizenship in Bulgaria is mainly based on the principle of ius sanguinis but can also be granted through naturalisation or birth. Article 12 of the 1998 Law establishes the general regime for naturalisation. Applicants are required to have resided legally in Bulgaria for at least ten years, since one must show that an applicant has been granted permission for permanent residence. The Constitution also grants citizenship to persons born in Bulgaria, unless they acquire another citizenship by descent, and children born to at least one Bulgarian parent.
Under Bulgarian law dual citizenship is permitted and there is no requirement for release of previous citizenship for:
• Spouses of Bulgarian citizens;
• Citizens of a Member State of the European Union, of a country party to the Agreement on the European Economic Area or of Switzerland;
• Citizens of countries with which Bulgaria has signed treaties which establish reciprocity.
Bulgarian citizens who acquire a second citizenship shall inform the Bulgarian authorities.