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International Legal Research: EU Treaties & Secondary Legislation

This Guide covers essential print and electronic resources for researching international and foreign law.

EU Treaties

Primary legislation in the EU system refers to treaties. Types of treaties include those establishing the EU (the Founding Treaties plus amendments), Accession Treaties, conventions between member states and treaties between the EU and third parties. The full text of these treaties as well as consolidated versions incorporating amendments at various points in time can be found at the Eur-Lex website.

Another source for EU treaty texts is Westlaw (WL Home > International Materials > Jurisdictions > European Union > European Union Treaties). A good, albeit not current, print source for EU treaties is the Encyclopedia of European Union Law, KJE4442.3 .E52.

The following founding and amending treaties are among the most important:

  • Treaty Establishing the European Economic Community, March 25, 1957 (aka Rome Treaty, EC Treaty and nka Treaty on the Functioning of the European Union (TFEU))
  • Treaty on European Union, February 7, 1992 (aka Maastricht Treaty or TEU)
  • Treaty of Amsterdam Amending the Treaty on European Union, the Treaties Establishing the European Communities and Certain Related Acts, October 2, 1997 (aka the Treaty of Amsterdam)
  • Treaty of Nice Amending the Treaty on European Union, the Treaties Establishing the European Communities and Certain Related Acts,2001 (aka the Treaty of Nice)
  • Treaty of Lisbon Amending the Treaty on European Union and the Treaty Establishing the European Communities, Dec. 13, 2007

The Treaty of Rome (1957) is somewhat analogous to our federal Constitution in that it creates the EU institutions and defines EU objectives. It also provides the basis and authority for EU legislation. The Rome Treaty is premised on the idea of a regional government of limited or derived powers. The Treaty of Lisbon significantly amended the EU's two core treaties, the Rome Treaty (EC Treaty) and the Maastrict Treaty (TEU). The Rome Treaty has been renamed the Treaty on the Functioning of the European Union (TFEU). The following chart provides a useful summary of the main features of each treaty.

From Raisch, Marilyn, European Union Law: an Integrated Guide to Electronic and Print Research (May, 2007).

See Bluebook Rule 21.9 (c) for help citing to EU treaties.

Secondary Legislation

Secondary (or ordinary) legislation in the EU system (not to be confused with secondary sources) include the following:

  • Regulations (not to be confused with U.S. agency regulations) have general application and are binding and directly applicable in each member country.
  • Directives are binding only as to the result. A directive establishes regional policy. Directives require implementation through national legislation in the member states. Most EU secondary legislation is in the form of directives.

In addition, the researcher should be aware of communications or nonlegislative acts like decisions and recommendations. Decisions are binding only on those to whom they are addressed. Recommendations include notices and guidelines which are not binding. Such nonbinding communications may be useful in terms of interpreting binding legislation.

The Integrated Guide referenced above contains the following document location chart, which covers treaties, EU legislation and court decisions.


In addition to the Eur-Lex website, most EU secondary legislation can be found via Westlaw  (WL Home > International Materials > Jurisdictions > European Union > European Union Legislation) or Lexis Advance (Lexis Advance Home > Explore Content > International > All Countries > European Union > All European Union Statutes & Legislation). The Eur-Lex website provides a template for simple searching. Westlaw and Lexis allow for more complex term and connector or Boolean searching.