The PES comprises national-level political parties from all member states of the European Union (EU) plus Norway. This includes major parties such as the Italian Democratic Party, the British Labour Party, the French Socialist Party, Social Democratic Party of Germany and the Spanish Socialist Workers' Party. Parties from a number of other European countries are also admitted to the PES as associate or observer parties. Most member, associate and observer parties are members of the wider Progressive Alliance or Socialist International.
The PES is currently led by its president Sergei Stanishev, a former Prime Minister of Bulgaria. Its political group in the European Parliament is the Progressive Alliance of Socialists and Democrats (S&D). The PES also operates in the Committee of the Regions (in the PES Group in the Committee of the Regions) and the European Council.
The party's English name is "Party of European Socialists". In addition, the following names are used in other languages:
- Albanian: Partia e Socialistëve Europianë
- Bosnian: Partija evropskih socijalista/Партија европских социјалиста
- Bulgarian: Партия на европейските социалисти
- Croatian: Stranka europskih socijalista
- Czech: Strana evropských socialistů
- Danish: De Europæiske Socialdemokrater
- Dutch: Partij van Europese Socialisten
- Estonian: Euroopa Sotsialistlik Partei
- Finnish: Euroopan sosialidemokraattinen puolue
- French: Parti socialiste européen
- German: Sozialdemokratische Partei Europas
- Greek: Ευρωπαϊκό Σοσιαλιστικό Κόμμα
- Hungarian: Európai Szocialisták Pártja
- Icelandic: Flokkur evrópskra sósíalista
- Irish: Páirtí na Sóisialaithe Eorpach
- Italian: Partito del Socialismo Europeo
- Latvian: Eiropas Sociāldemokrātiskā partija
- Lithuanian: Europos socialistų partija
- Luxembourgish: Partei vun den Europäesche Sozialisten
- Macedonian: Партија на европските социјалисти
- Maltese: Partit tas-Soċjalisti Ewropej
- Norwegian: Det europeiske sosialdemokratiske partiet
- Polish: Partia Europejskich Socjalistów
- Portuguese: Partido Socialista Europeu
- Romanian: Partidul Socialiștilor Europeni
- Serbian: Партија европских социјалиста
- Slovak: Strana európskych socialistov
- Slovene: Stranka evropskih socialistov
- Spanish: Partido de los Socialistas Europeos
- Swedish: Europeiska socialdemokratiska partiet
In 1961, the Socialists in the European Parliament attempted to produce a common 'European Socialist Programme' but this was neglected due to the applications of Britain, Denmark, Ireland and Norway to join the European Community. The Socialists' 1962 congress pushed for greater democratisation and powers for Parliament, though it was only in 1969 that this possibility was examined by the member states.
In 1973, Denmark, Ireland and the United Kingdom joined the European Community, bringing in new parties from these countries. The enlarged Socialist Congress met in Bonn and inaugurated the Confederation of the Socialist Parties of the European Community. The Congress also passed a resolution on social policy, including the right to decent work, social security, democracy and equality in the European economy. In 1978, the Confederation of Socialist Parties approved the first common European election Manifesto. It focused on several goals among which the most important were to ensure a right to decent work, fight pollution, end discrimination, protect the consumer and promote peace, human rights and civil liberties.
At its Luxembourg Congress in 1980, the Confederation of Socialist Parties approved its first Statute. The accession of Greece to the EU in 1981, followed by Spain and Portugal in 1986, brought in more parties.
In 1984, a common Socialist election manifesto proposed a socialist remedy for the economic crisis of the time by establishing a link between industrial production, protection of fundamental social benefits, and the fight for an improved quality of life.
In 1992, with the European Community becoming the European Union and with the Treaty of Maastricht establishing the framework for political parties at a European level, the Confederation of Socialist Parties voted to transform itself into the Party of European Socialists. The party's first programme concentrated on job creation, democracy, gender equality, environmental and consumer protection, peace and security, regulation of immigration, discouragement of racism and fighting organised crime.
- Social Democratic Party of Austria
- Socialist Party (Francophone) and the Socialist Party (Flemish) of Belgium
- Social Democrats of Denmark
- Socialist Party of France
- Social Democratic Party of Germany
- Panhellenic Socialist Movement of Greece
- Labour Party of Ireland
- Italian Democratic Socialist Party, Italian Socialist Party and Democratic Party of the Left of Italy
- Luxembourg Socialist Workers' Party
- Labour Party of the Netherlands
- Socialist Party of Portugal
- Spanish Socialist Workers' Party
- Swedish Social Democratic Party
- Labour Party and Social Democratic and Labour Party of the UK
In 2004 Poul Nyrup Rasmussen defeated Giuliano Amato to be elected President of the PES, succeeding Robin Cook in the post. He was re-elected for a further 2.5 years at the PES Congress in Porto on 8 December 2006 and again at the Prague Congress in 2009.
Mr Rasmussen stood down at the PES Progressive Convention in Brussels on 24 November 2011. He was replaced as interim president by Sergei Stanishev, chairman of the Bulgarian Socialist Party (BSP) and former prime minister of Bulgaria.
On 28-29 September 2012, the PES Congress in Brussels Congress elected interim president Sergei Stanishev as full President, as well as four deputies: Jean-Christophe Cambadélis (1st Vice-President – PS), Elena Valenciano (PSOE), Jan Royall (Labour) and Katarína Neveďalová (Smer-SD). The same Congress elected Achim Post (SPD) as its new secretary general, and adopted a process which it described as "democratic and transparent" for electing its next candidate for Commission President in 2014. The PES had already agreed in 2011 to use a PES presidential primary for the election.
The PES has thirty-three full member parties from each of the twenty-eight EU member states and Norway. There are a further thirteen associate and twelve observer parties from other European countries.
The President (currently former Prime Minister of Bulgaria Sergei Stanishev) represents the party on a daily basis and chairs the Presidency, which also consists of the Secretary General, President of the S&D group in Parliament and one representative per full/associate member party and organisation. They may also be joined by the President of the European Parliament (if a PES member), a PES European Commissioner and a representative from associate parties and organisations.
The list below shows PES Presidents and the presidents of its predecessors.
The parties meet at the party Congress twice every five years to decide on political orientation, such as adopting manifestos ahead of elections. Every year that the Congress does not meet, the Council (a smaller version of the Congress) shapes PES policy. The Congress also elects the party's President, Vice Presidents and the Presidency.
The Leader's Conference brings together Prime Ministers and Party Leaders from PES parties three to four times a year to agree strategies and resolutions.
In December 2009, the PES decided to put forward a candidate for Commission President at all subsequent elections. On 1 March 2014, the PES organised for the first time a European election Congress where a Common Manifesto  was adopted and the Common Candidate designate for the post of Commission President, Martin Schulz, was elected by over a thousand participants in Rome, Italy. PES member parties across Europe joined forces to campaign for the European elections, and a mass grassroots movement sprang up in support of Martin Schulz, aiming to ‘knock the vote’ in support of his candidacy.
PES in the European institutions
European Commissioners are meant to remain independent, however there has been an increasing degree of politicisation within the Commission. In the current European Commission, eight of the Commissioners belong to the PES family.
Of the 28 heads of state and government that are members of the European Council, seven are from the PES, and therefore regularly attend PES summits to prepare for European Council meetings.
Party-alignment at the European Council is often loose, but has been the basis of some intergovernmental cooperation. At present seven countries are led by a PES-affiliated leader, who represents that state at the European Council: Spain (Pedro Sánchez), Portugal (Antonio Costa), Malta (Joseph Muscat), Slovakia (Peter Pellegrini), Denmark (Mette Frederiksen), Finland (Antti Rinne) and Sweden (Stefan Löfven).
The makeup of national delegations to the Council of Ministers is at some times subject to coalitions: for the above governments led by a PES party, that party may not be present in all Council configurations; in other governments led by non-PES parties a PES minister may be its representative for certain portfolios. PES is in coalition in a further seven countries: Estonia, France, Germany, Luxembourg, Romania, Slovenia and Italy.