Following the conflicts in the late 1990s in the countries of the former Yugoslavia, the prospect of membership in the Euro-Atlantic community and the active presence of the United States in the Western Balkan region provided a level of stability that allowed most regional countries to pursue reform and adopt Western values. Slovenia and Croatia joined the European Union (EU) and, along with Albania, also joined NATO. Montenegro became NATO's 29th member on June 3, 2017. Other nations of the Balkans are at various stages on the path toward EU or NATO membership. However, many observers in Europe and the United States have been concerned that political stability in the Western Balkans remains tenuous. Several of these countries have experienced governmental and political crises, sometimes involving third-party interference, stagnating economies, high unemployment, and an exodus of people from the region. These crises have raised cautions that the continuation of or sudden increase in these factors could provide a vacuum in which outside political meddling, transnational crime, radicalization, or terrorism could flourish. At the center of the Balkans lies Serbia, which occupies a key strategic juncture at the social, political, and geographic crossroads between Eastern and Western Europe. Despite difficult historical relations with its neighbors, its ongoing dispute with Kosovo, recent concerns over its commitment to democratic development, and the desire to balance its aspirations toward the West with its historical ties to Russia, Serbia is seen by some as more stable politically than several of its neighbors. Some also view Serbia as potentially the engine of economic growth for the entire Balkan region. At the same time, others view Serbia as an important piece in the geostrategic competition in the Western Balkans between the EU, the United States, and Russia. U.S. relations with Serbia have been rocky at times, due to past U.S. interventions in the conflicts in Bosnia and Kosovo and the U.S. recognition of Kosovo's independence. Nevertheless, relations between Washington and Belgrade seem to have improved recently, and today they appear to be cordial. Between 2001 and 2017, the United States provided close to $800 million in aid to Serbia to help stimulate economic growth, strengthen the justice system, and promote good governance. Despite the U.S. disagreement with Serbia over Kosovo's independence and the mixed messages Washington believes Serbia sends over its relations with Moscow, the United States continues to support Serbia's efforts to join the EU. At the same time, the United States has sought to strengthen its own relationship with Serbia through deepening cooperation based on mutual interests and respect. Many Balkan watchers believe the EU's commitment to further integration of the Balkans, despite its declaratory support, has been distracted by the EU migration crisis and the negotiations with the United Kingdom over its departure from the union. These observers, in both Washington and the Balkans, believe the United States needs to reinvigorate its former strategy of active engagement with the Western Balkans, and in particular its relations with Serbia. Congressional interest in Serbia (and Kosovo) dates to the 1991-1999 conflicts in the Western Balkans. Over time, Congress has established Member caucuses on both Kosovo and Serbia and has held several hearings on the Western Balkans. Recently, the Serb Caucus in the House noted the 100th anniversary of Woodrow Wilson's "day of prayer" for the people of Serbia. Many Members support Kosovo's independence, the efforts at reconciliation between Serbia and Kosovo, and EU membership for both countries, but other Members have expressed skepticism about Serbia's relations with Russia or the future viability of the Serbia-Kosovo coexistence. This report provides a brief overview of Serbia and U.S. relations with Belgrade.