This thesis examines different legal aspects of the enlargement of the European Union and the relations between the EU and Turkey. As a preliminary remark, it is established that only two articles of the EU-Treaty address the question of enlargement. The first one, article 49 1 states that the applicant country has to respect the principles set out in article 6(1) 2, i.e. liberty, democracy, respect for human rights and fundamental freedoms and the rule of law. In reality, these articles entail a long and complicated process, where the Commission is particularly involved. There is a difference between when an entity can qualify as a European state, a prerequisite for the acceptation of the application, and that a state later on will be accepted as a Member State. This hierarchy will be highlighted and further discussed. Compliance with the Copenhagen Criteria 3 is of vital importance before a state is recognized as a candidate state. However, total compliance does not seem to be necessary. In connection to this, the body of EU-law, the so-called acquis communitaire, is discussed. All new Member States have to implement and comply with the “acquis”. The political trend within the EU is moving towards a constantly deepening cooperation. The European Union of today is more of a political Union than an economical Union, which means that a constantly evolving EU legislation renders accession to the Union increasingly difficult. The issue of human rights is of importance during the candidacy process, since it forms a part of the Copenhagen Criteria and EU legislation. The jurisprudence of the ECJ (European Court of Justice) has varied during the years, but the ECHR (European Court of Human Rights ) is often mentioned as an important source of inspiration. Formally, a higher standard in this area is required from candidate states than from Member States. This might be