Serbia and Montenegro was a country in southeastern Europe, formed in 1992 from two former republics of the Socialist Federal Republic of Yugoslavia (SFR Yugoslavia): Serbia and Montenegro. Following the breakup of Yugoslavia, it was established in 1992 as a federation called the Federal Republic of Yugoslavia (FRY; Serbo-Croatian, Serbian: Savezna Republika Jugoslavija, Савезна Република Југославија; SRJ, СРЈ). In 2003, it was reconstituted as a political union called the State Union of Serbia and Montenegro (Serbo-Croatian, Serbian: Državna zajednica Srbija i Crna Gora, Државна заједница Србија и Црна Гора; SCG, СЦГ).
Federal Repubic of Yugoslavia aspired to be a sole legal successor to SFR Yugoslavia (Yugoslavia “proper”), but those claims were opposed by other former republics.
The United Nations also denied its request to automatically continue the membership of the former state. Eventually, after ousting of Slobodan Milošević from power in Serbia in 2000, the country rescinded those aspirations and accepted the opinion of Badinter Arbitration Committee about shared succession, and reapplied for UN membership. From 1992 to 2000, some countries, including the United States, referred to FR Yugoslavia as “Serbia and Montenegro”.
A loose confederation, Serbia and Montenegro were united only in certain realms, such as defense. The two constituent republics functioned separately throughout the period of the Federal Republic, and continued to operate under separate economic policies, as well as using separate currencies (the euro was the only legal tender in Montenegro).
On 21 May 2006, the Montenegrin independence referendum was held. Final official results indicated on 31 May that 55.5% of voters voted in favor of independence. The state union effectively came to an end after Montenegro’s formal declaration of independence on 3 June 2006, and Serbia’s formal declaration of independence on 5 June. Many view this as the final end of what was left of the former Yugoslavia.
Notes from Wikipedia