Serbian nationality law
Citizenship of Serbia is regulated by the "Citizenship Law of the Republic of Serbia", adopted in 2004 and based primarily on the principle of Jus sanguinis. Article 23 of the citizenship law stipulates that any foreign national with Serbian descent has the right to acquire Serbian citizenship by written request. The law also allows dual citizenship, allowing an individual the right to retain his or her current citizenship and receive Serbian citizenship. The 2007 amendments enabled ethnic Serbs residing outside Serbia the right to citizenship. These amendments, adopted after the Montenegrin independence referendum, 2006, also allowed citizens  of Montenegro living in Serbia the right to gain citizenship, if they submit the request within a 5-year period. Visa requirement for Serbian citizens. In 2015, Serbian citizens had visa-free or visa on arrival access to 110 countries and territories, ranking the Serbian passport 43rd in the world according to the Visa Restrictions Index. The Serbian passport is one of the 5 passports with the most improved rating globally since 2006 in terms of the number of countries that its holders may visit without a visa.