This article analyses the Treaty of Lisbon, a Treaty whose fate hangs in the balance following the Irish ‘no’ in June 2008. It is structured as follows. First, the processes leading to the adoption and ratification of the Treaty are examined. Second, the structure of the Treaty and the institutional framework are explained, together with changes to the social provisions. Third, the possible impact which the Treaty, if ratified, would have on labour law is discussed. Particular attention is devoted to the changes in the values, aims and objectives of the Union and to the European Union's proposed accession to the European Convention for the Protection of Human Rights and Fundamental Freedoms. It is argued that these changes may influence the internal market case law of the Court of Justice, which, as the Viking, Laval and Ruffert cases demonstrate, represents a significant threat to national labour laws and practices.