Citizenship of the United States
A person who is considered a citizen by more than one nation has "dual citizenship". It is possible for a United States citizen to have dual citizenship; this can be achieved in various ways, such as by birth in the United States to a parent who is a citizen of a foreign country (or in certain circumstances the foreign nationality may be transmitted even by a grandparent) by birth in another country to a parent(s) who is/are a United States citizen/s, or by having parents who are citizens of different countries. Anyone who becomes a naturalized U.S. citizen is required to renounce any prior "allegiance" to other countries during the naturalization ceremony; however, this renunciation of allegiance renunciation of citizenship to those countries.
Ukrainian nationality law
Ukrainian law currently does not recognise dual citizenship. However, there are citizens of Ukraine who hold dual citizenship. Ukrainian law states that (after gaining Ukrainian citizenship) the new Ukrainian citizen must renounce its non-Ukrainian citizenship(s) within two years. A 2009 estimate put the number of Ukrainians with more than one passport from 300,000 to a few million. Within Ukrainian boundaries Ukrainian citizens who also hold multiple citizenships are considered to be solely Ukrainian citizens.
On February 8, 2014, the Verkhovna Rada proposed a bill to criminalize the act of holding two citizenships.