The European Union (EU) has increasingly called for regulatory agreements in the World Trade Organization (WTO) in areas such as investment, competition, environment, and labour. Why has the EU attempted to satisfy such new demands by pursuing regulatory goals within the WTO rather than within other international organizations? I suggest two reasons for the EU's choice of the WTO. First, the nature of issue linkage in international trade negotiations has changed from exclusive exchanges of market access to the exchange of market access for regulation. Owing to the diversity of domestic constituency demands and consensus decision-making, the EU is particularly reliant on such broad issue linkages. And second, judicialization and the possibility of cross-retaliation in the WTO have enhanced the credibility of WTO commitments, increasing the organization's attractiveness for issue linkages across policy fields. I show how these two factors have contributed to the EU's attempt to place regulatory issues on the agenda of the Doha Development Round.