The Union of Democrats for Europe (Italian: Unione Democratici per l'Europa, UDEUR), also known as UDEUR Populars (Popolari UDEUR), was a minor centrist, Christian-democratic political party in Italy.

Led by Clemente Mastella, minister of Labour in Berlusconi I Cabinet (1994–1995), minister of Justice in Prodi II Cabinet (2006–2008) and current mayor of Benevento (since 2016), the party has been at times very strong in Southern Italy, but almost irrelevant in Northern Italy. After a decline in terms of popularity in 2007–2008, the party resisted only in Campania, Mastella's heartland, and few other regions. The party was briefly revived in the run-up of the 2018 general election.

The UDEUR emerged in May 1999 at the breakup of the Democratic Union for the Republic (UDR). This party had been founded in June 1998, under the leadership of Francesco Cossiga, by the merger of Rocco Buttiglione's United Christian Democrats, Mastella's Christian Democrats for the Republic (a splinter group from the Christian Democratic Centre), the Segni Pact and splinters from Forza Italia, National Alliance and Lega Nord. At its foundation, the UDEUR included a minister in Massimo D'Alema's government, Salvatore Cardinale at the ministry of Communications.

At its electoral debut at the 1999 European Parliament election, the party received 1.6% of the vote, having its strongholds in the South (5.1% in Campania, 3.4% in Basilicata, 4.4% in Calabria and 7.1% in Sicily).

In the run-up to the 2001 general election the UDEUR joined the Democracy is Freedom – The Daisy (DL) electoral list, along with the Italian People's Party, The Democrats and Italian Renewal. Under the leadership of Francesco Rutelli, who ran also as leader of the entire The Olive Tree centre-left coalition, DL gained 14.6% of the vote. The list's success led to a debate over forming a joint party. When DL was effectively transformed into a party in early 2002, the UDEUR refused to join and remained an independent party within the centre-left.

In 2004 the party changed its official name to UDEUR Populars and amended its symbol accordingly (it would later go back to its original name).

At the 2004 European Parliament election UDEUR achieved 1.3% of the national vote (5.4% in Campania, 4.0% in Basilicata, 3.8% in Calabria and 2.7% in Sicily), enough to elect an MEP, who sat in the European People's Party – European Democrats (EPP–ED) group.

At the 2005 regional elections the party had its best result ever, having scored 10.3% in Campania, 11.1% in Basilicata and 8.7% in Calabria.