This paper analyses the EU-Ukraine Association Agreement (AA). It argues that this new legal framework, which has the objective to establish a unique form of political association and economic integration, is characterised by three specific features: comprehensiveness, complexity and conditionality. After a brief background of the EU-Ukraine relations, the following aspects are scrutinised: legal basis and objectives, institutional framework and mechanisms of enhanced conditionality and legislative approximation. In addition, constitutional challenges for the effective implementation of the EU-Ukraine AA are discussed. Based upon a comparison with other EU external agreements, it is demonstrated that the AA is an innovative legal instrument providing for a new type of integration without membership.