An increasing number of persons in the EU member states are working in forms of employment that are considered atypical, i.e. occupations without clearly determined employer-employee relations, working hours, working place, wages, social-security coverage, or effective protection by labour law. Particularly since the economic and financial crisis of 2007-2008, and with an increasing digitalisation of the labour markets, new forms of atypical work have evolved, and the number of people working in existing forms of atypical employment grows. This research project analyses how the EU institutions and member states with the highest impact on EU legislation in the field of employment and social policy have come to define atypical work and have attempted to regulate it, and how their notions of atypical work have changed over the last ten years. The project points out the incoherence of these notions, and the resulting inter- and intra-institutional tensions as well as their impact on EU legislation. Based on a large collection of documents, the most important internal and external factors are studied that have an impact on the different understandings of ‘atypical work’ at EU level, and on the involved actors’ connected behaviour.