This article explores and offers an in-depth empirical account of the efforts made by the centre-right and federalist European People’s Party (EPP) to play a role in the 1996-97 Intergovernmental Conference (IGC) and negotiations leading to the adoption of the Amsterdam treaty in 1997. Before and during the course of the IGC the EPP made concerted efforts to muster a consensus around its priorities, concerning institutions as well as issues, and for a substantial treaty reform. EPP bodies convened and set out their views on the IGC, with the purpose of trying to work out compromises and reach agreement on the issues in order to strengthen the position in the IGC negotiations. In sum, there was significant activity in the EPP. The findings carry implications for research on the transnationalization of politics, in particular transnational party and elite networks, and the EU and its constitutionalization.