The project aims to examine interest groups’ participation in EU policymaking and to investigate a fundamental question regarding the EU interest representation system: under what conditions are interest groups’ policy demands integrated into the policymaking process and translated into policy outcomes? In other words, what factors explain interest groups’ success in influencing the content of EU legislative proposals?The project aims to answer this question by examining interest groups’ lobbying during the policy formulation and policy shaping stages of the EU policymaking process and focuses on lobbying in the European Commission and the European Parliament, across four policy areas.To explain lobbying success the project will elaborate and empirically test an explanatory framework that emphasizes the importance of the policy context in which lobbying takes place. This context is defined in terms of: characteristics of policy issues; the aggregate distribution of interest groups’ policy demands; and the policy network ties established between interest groups themselves and interest groups and policymakers. The project proposes a research design that allows a systematic, empirical testing of the theoretical framework with the help of multi-level statistical models and social network analysis.The project addresses and contributes to the scholarship on EU lobbying, policymaking and decision-making processes. Theoretically, the project innovates by proposing an explanatory framework that emphasizes the relational environment established both among interest organisations themselves, and among organisations and policymakers, and the aggregate distribution of demands articulated by interest groups.These dimensions have not been systematically studied in the literature at policy issue level.Methodologically, the project innovates by adopting an original research design that allows a disaggregate empirical investigation of interest groups' demands in the EU policymaking.