Level 7 of 10: Regional blocs and supranational bodies

Mercosur

Mercosur (the Southern Common Market) is a South American trade bloc created by the Treaty of Asunción, signed on 26 March 1991 by Argentina, Brazil, Paraguay and Uruguay; Bolivia became a full State Party on 7 August 2024. Under the Ouro Preto Protocol its top body, the Common Market Council of foreign and economy ministers, takes decisions by consensus with all States Parties present, and those rules are binding on members. Colombia's foreign ministry records Venezuela as suspended since August 2017.

The UK and the Mercosur

The UK is not a member or associated state. Colombia's foreign ministry lists Mercosur's associated states as Chile, Colombia, Ecuador, Guyana, Panama, Peru, Suriname and Bolivia.

Key figures

What it decides

• The Common Market Council is Mercosur's highest body, in charge of the political direction of integration and of decisions to meet the Treaty of Asunción's aims (Ouro Preto Protocol, Article 3); it is made up of foreign and economy ministers (Article 4).
• Decisions of Mercosur bodies are taken by consensus with all States Parties present (Article 37).
• Rules made by Mercosur bodies are binding and, where needed, must be incorporated into national law (Article 42).
• Mercosur has legal personality under international law (Article 34).
• The Treaty of Asunción commits States Parties to a common market with free movement of goods, services and factors of production, a common external tariff and coordinated economic policies.

Records you can check

• Treaty of Asunción (Portuguese text)
  Mercosur's founding treaty, hosted by Brazil's Chamber of Deputies
• Ouro Preto Protocol (Portuguese text)
  Mercosur's institutional structure and decision rules
• EU-Mercosur trade relationship
  European Commission figures and documents on EU-Mercosur trade and the 2026 agreements

Common questions

Which countries are in Mercosur?

Argentina, Brazil, Paraguay and Uruguay founded Mercosur in 1991, and Bolivia became a State Party on 7 August 2024, according to Mercosur meeting records. Colombia's foreign ministry lists Venezuela as suspended since August 2017.

Is the UK in Mercosur?

No. Mercosur's States Parties and associated states are all South and Central American countries.

What is the EU-Mercosur agreement?

The European Commission says the EU and Mercosur signed a Partnership Agreement and an interim Trade Agreement on 17 January 2026, with the interim agreement applied provisionally from 1 May 2026.

How does Mercosur make decisions?

By consensus. Article 37 of the Ouro Preto Protocol says decisions of Mercosur bodies are taken by consensus with all States Parties present.

How much does the EU trade with Mercosur?

The European Commission reports EU exports of €53.3 billion to the four founding Mercosur countries in 2025 and imports from them of €56.1 billion.

Other bodies at level 7

• African Union
• Association of Southeast Asian Nations
• Council of Europe and the European Court of Human Rights
• European Central Bank
• European Court of Human Rights
• European Union (incl. Parliament, Commission, Council)
• Gulf Cooperation Council
• Shanghai Cooperation Organisation

Sources

• Tratado de Assunção (Câmara dos Deputados), read 20 October 2026
• Protocolo de Ouro Preto, Decreto Legislativo nº 188 de 1995 (Câmara dos Deputados), read 20 October 2026
• Acta GANEP-Bolivia 2024 (Mercosur), read 20 October 2026
• Mercado Común del Sur - Mercosur (Cancillería de Colombia), read 20 October 2026
• EU trade relations with Mercosur (European Commission), read 20 October 2026