little knowledge on how and why the conditions of irregular migrants vary so dramatically across Europe. Key to this variation are countries’ and sectors’ different institutional landscapes. Understanding the role and effects of institutional variations, and the interests with which they are associated, is a critical precondition for effective national and EU policies on irregular migrants. PRIME will provide a new comparative institutional approach to understanding the conditions and vulnerabilities of irregular migrants in Europe. Understanding ‘irregularity’ as a complex, gendered status it will conduct large-scale surveys, structured policy analysis, and qualitative interviews with irregular migrants, employers, policy actors, interest groups and voters across eight European countries. PRIME will generate new analysis on how migrants’ outcomes and experiences are shaped by national socio-economic institutions (including national labour market regulations and welfare institutions), sectoral policies, and the actions and interests of migrants and citizens. PRIME will examine the inevitable goal conflicts that arise in policy-making toward irregular migrants, and propose strategies for how they may be best managed across different institutional settings to enable more effective policy-making that benefits both migrants and host communities. To engage its key target groups (national and EU policy actors, interest groups, and the scientific community), PRIME will create a ‘PRIME-Hub’ for joint knowledge creation and exchange which will extend beyond the project life-time. In this way PRIME will go beyond simple ‘best-practice’ models by providing evidence on context-sensitive strategies and policy tools as a basis for achievable and sustainable policy-making on irregular migrants.