There has been considerable debate about power delegation in EU trade politics, but few studies explore the question of how and why agency losses occur. Focusing on agricultural issues in the Doha Round, this article analyses the impact of agency losses (agency shirking and agency slippage) in the process of power delegation in EU trade politics. Are agency losses the result of the delegation structure, which stimulates the agent to adopt a different position from the principals (agency slippage), or do conflict situations arise because of conflicting interests between the interests of the Member States and those of the European Commission (agency shirking)? Based on information collected from Agence Europe and interviews with European officials, the main conclusions are that: (1) the Council–Commission relationship can be conflict-laden or co-operative depending on the negotiating stage at the international level; (2) a low degree of interest alignment among Member States increases the Commission’s discretion at the international level; (3) inter-institutional conflict weakens the EU negotiating position at the international level because the other WTO members know that the EU is divided and ask for further concessions.